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Beef heifer fertility: importance of management practices and technological advancements
Moorey, Sarah E.; Biase, Fernando H. (2020-10-01)
The development of replacement heifers is at the core of cow-calf beef production systems. In 2020, the USDA, National Agricultural Statistics Service reported 5.771 million beef heifers, 500 pounds and over, are under development for cow replacement. A compilation of data from several studies indicate that between 85% and 95% of these heifers will become pregnant in their first breeding season. Several thousands of heifers being raised for replacement may not deliver a calf on their first breeding season and result in economic losses to cow-calf producers. Many management procedures have been developed to maximize the reproductive potential of beef heifers. Such approaches include, but are not limited to the following: nutritional management for controlled weight gain, identification of reproductive maturity by physiological and morphological indicators, and the implementation of an estrous synchronization program. The implementation of management strategies has important positive impact(s) on the reproductive efficiency of heifers. There are limitations, however, because some heifers deemed ready to enter their first breeding season do not become pregnant. In parallel, genetic selection for fertility-related traits in beef heifers have not promoted major genetic gains on this particular area, most likely due to low heritability of female fertility traits in cattle. Technologies such as antral follicle counting, DNA genotyping and RNA profiling are being investigated as a means to aid in the identification of heifers of low fertility potential. To date, many polymorphisms have been associated with heifer fertility, but no DNA markers have been identified across herds. Antral follicle count is an indication of the ovarian reserve and is an indicator of the reproductive health of a heifer. We have been working on the identification of transcriptome profiles in heifers associated with pregnancy outcome. Our current investigations integrating protein-coding transcript abundance and artificial intelligence have identified the potential for bloodborne transcript abundance to be used as indicators of fertility potential in beef heifers. In summary, there is an ongoing pressure for reducing costs and increasing efficiency in cow-calf production systems, and new technologies can help reduce the long-standing limitations in beef heifer fertility.
Centennial Review: The chicken yolk sac is a multifunctional organ
Wong, Eric A.; Uni, Z. (Elsevier, 2020-12-08)
The yolk sac (YS) consists of the yolk, which supplies nutrients, and the YS tissue, which surrounds the yolk and provides essential metabolic functions for the developing embryo. The YS tissue is derived from the midgut of the embryo and consists of a layer of endodermal epithelial cells (EEC) in contact with the yolk contents, a mesodermal layer that contains the vascular system and an outer ectodermal layer. The YS tissue is a multifunctional organ that provides essential functions such as host immunity, nutrient uptake, carbohydrate and lipid metabolism, and erythropoiesis. The YS tissue plays a role in immunity by the transport of maternal antibodies in the yolk to the embryonic circulation that feeds the developing embryo. In addition, the YS tissue expresses high mRNA levels of the host defense peptide, avian b-defensin 10 during mid embryogenesis. Owing to its origin, the YS EEC share some functional properties with intestinal epithelial cells such as expression of transporters for amino acids, peptides, monosaccharides, fatty acids, and minerals. The YS tissue stores glycogen and expresses enzymes for glycogen synthesis and breakdown and glucogenesis. This carbohydrate metabolism may play an important role in the hatching process. The mesodermal layer of the YS tissue is the site for erythropoiesis and provides erythrocytes before the maturation of the bone marrow. Other functions of the YS tissue involve synthesis of plasma proteins, lipid transport and cholesterol metabolism, and synthesis of thyroxine. Thus, the YS is an essential organ for the growth, development, and health of the developing embryo. This review will provide an overview of the studies that have investigated the functionalities of the YS tissue at the cellular and molecular levels with a focus on chickens.
Combination of probiotics and coccidiosis vaccine enhances protection against an Eimeria challenge
Ritzi, Miranda M.; Abdelrahman, Wael; van-Heerden, Kobus; Mohnl, Michaela; Barrett, Nathaniel W.; Dalloul, Rami A. (BMC, 2016-11-08)
Coccidiosis is endemic in the commercial broiler industry capable of inflicting devastating economic losses to poultry operations. Vaccines are relatively effective in controlling the disease; their efficacy could potentially be improved with concurrent use of probiotics as evaluated in this study using an Eimeria challenge. Day of hatch 400 Cobb-500 male broilers were assigned to one of four treatment groups including control (CON), vaccine-only gel application (VNC), probiotic-only gel application (NPC), and vaccine-plus-probiotic gel application (VPC). Birds were placed in floor pens (6 replicate pens/treatment, 16–17 birds/pen). NPC and VPC birds received the probiotics in the water on days 2–4, 8, 14–20, 22, 29, and 34–36. On day 15, birds were mildly challenged with 0.5 mL of a mixed oral inoculum of Eimeria sp. prepared with the coccidiosis vaccine at 10× the vaccination dose. Performance measurements were recorded on first day and weekly afterwards, and lesion scores were evaluated 6 days post-challenge. Overall, the probiotics and coccidiosis vaccine resulted in an enhanced protective effect against the challenge, with VPC birds exhibiting lower lesion scores in the duodenum than VNC or NPC birds. Birds in the VPC treatment also demonstrated higher weight gains during days 1–15, days 7–15, and days 21–28 when compared to the VNC birds. These results suggest that the combination of probiotics and coccidiosis vaccines could enhance performance and provide an additional protective effect against a mixed Eimeria challenge.
Comparison of reproductive performance of AI- and natural service-sired beef females under commercial management
Marrella, Mackenzie A.; White, Robin R.; Dias, Nicholas W.; Timlin, Claire; Pancini, Stefania; Currin, John F.; Clark, Sherrie G.; Stewart, Jamie L.; Mercadante, Vitor R. G.; Bradford, Heather L. (Oxford University Press, 2021-07)
The objective of this study was to assess differences in reproductive performance of natural service and artificial insemination (AI) sired beef females based on pregnancy outcomes, age at first calving, and calving interval. Data were sourced from 8,938 cows sired by AI bulls and 3,320 cows sired by natural service bulls between 2010 and 2017. All cows were in a commercial Angus herd with 17 management units located throughout Virginia and represented spring and fall calving seasons. All calves were born to dams managed with estrus synchronization. Pregnancy was analyzed with generalized linear mixed models and other reproductive measures with linear mixed models in R. Six models were evaluated with the dependent variables of pregnancy status at the first diagnosis, pregnancy status at the second diagnosis, pregnancy type (AI or natural service) at the first diagnosis, pregnancy type at the second diagnosis, calving interval, and age at first calving. Independent variables differed by model but included sire type of the female (AI or natural service), prebreeding measures of age, weight, and body condition score, postpartum interval, sex of the calf nursing the cow, and management group. No differences were observed between AI- and natural service-sired females based on pregnancy status at first and second pregnancy diagnosis (P > 0.05). Sire type was only found to be significant for age at first calving (P < 0.05) with AI-sired females being 26.6 ± 1.6 d older at their first calving, which was expected because AI-sired females were born early in the calving season making them older at breeding. Surprisingly, age and body condition score were not significant predictors of pregnancy (P > 0.05). Body weight at breeding was not significant for pregnancy (P > 0.05) but was significant for age at first calving (P < 0.05). These data suggested that lighter heifers calved earlier which contradicts our original hypothesis. Overall, commercial Angus females sired by AI or natural service bulls had similar reproductive performance. Factors that were commonly associated with reproductive success were not significant in this commercial Angus herd managed with estrus synchronization. Given the size of these data, the importance of body condition, age, and weight should be reassessed in modern genetics and management practices.
Development and validation of a house finch interleukin-1β (HfIL-1β) ELISA system
Kim, Sungwon; Park, Myeongseon; Leon, Ariel E.; Adelman, James S.; Hawley, Dana M.; Dalloul, Rami A. (2017-08-30)
Background A unique clade of the bacterium Mycoplasma gallisepticum (MG), which causes chronic respiratory disease in poultry, has resulted in annual epidemics of conjunctivitis in North American house finches since the 1990s. Currently, few immunological tools have been validated for this songbird species. Interleukin-1β (IL-1β) is a prototypic multifunctional cytokine and can affect almost every cell type during Mycoplasma infection. The overall goal of this study was to develop and validate a direct ELISA assay for house finch IL-1β (HfIL-1β) using a cross-reactive chicken antibody. Methods A direct ELISA approach was used to develop this system using two different coating methods, carbonate and dehydration. In both methods, antigens (recombinant HfIL-1b or house finch plasma) were serially diluted in carbonate-bicarbonate coating buffer and either incubated at 4 °C overnight or at 60 °C on a heating block for 2 hr. To generate the standard curve, rHfIL-1b protein was serially diluted at 0, 3, 6, 9, 12, 15, 18, 21, and 24 ng/mL. Following blocking and washing, anti-chicken IL-1b polyclonal antibody was added, plates were later incubated with detecting antibodies, and reactions developed with tetramethylbenzidine solution. Results A commercially available anti-chicken IL-1β (ChIL-1β) polyclonal antibody (pAb) cross-reacted with house finch plasma IL-1β as well as bacterially expressed recombinant house finch IL-1β (rHfIL-1β) in immunoblotting assays. In a direct ELISA system, rHfIL-1β could not be detected by an anti-ChIL-1β pAb when the antigen was coated with carbonate-bicarbonate buffer at 4°C overnight. However, rHfIL-1β was detected by the anti-ChIL-1β pAb when the antigen was coated using a dehydration method by heat (60°C). Using the developed direct ELISA for HfIL-1β with commercial anti-ChIL-1β pAb, we were able to measure plasma IL-1β levels from house finches. Conclusions Based on high amino acid sequence homology, we hypothesized and demonstrated cross-reactivity of anti-ChIL-1β pAb and HfIL-1β. Then, we developed and validated a direct ELISA system for HfIL-1β using a commercial anti-ChIL-1β pAb by measuring plasma HfIL-1β in house finches.
Dietary Non-Drug Feed Additive as an Alternative for Antibiotic Growth Promoters for Broilers During a Necrotic Enteritis Challenge
Calik, Ali; Omara, Islam I.; White, Mallory B.; Evans, Nicholas P.; Karnezos, T. Peter; Dalloul, Rami A. (MDPI, 2019-08-13)
Necrotic enteritis, caused by Clostridium perfringens, is an enteric disease that leads to poor performance and increased mortality, resulting in significant economic losses in poultry production. This study evaluated the effects of a proprietary prebiotic, probiotic, and plant extract blend on performance of broilers during coccidiosis challenge leading to necrotic enteritis (NE). In total, 744 Cobb500 male broilers were randomly allocated to 3 treatments (8 replicates, 31 birds/pen) including, the negative control (NC) fed a basal diet; the positive control (PC) fed a basal diet with Virginiamycin; and the additive group fed basal diet with a blend of prebiotic, probiotic, and plant extract (BSN). A unique, naturally occurring NE model developed to mimic field conditions was implemented to challenge the birds. This model consists of spraying a concentrated commercial coccidiosis vaccine on litter and feed upon bird placement, which, in conjunction with the presence of C. perfringens spores in the environment, leads to the development of a NE outbreak one week post vaccine application. At the onset of NE on d7, three birds/pen were selected for scoring NE lesions. Body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were recorded on days 7, 14, 28, and 42. Carcass composition was assessed by dual energy X-ray absorptiometry (DXA) analysis on day 42. Dietary supplementation of BSN significantly (p < 0.05) improved FCR during starter and grower periods. Dietary treatments had no effect on NE lesions in the small intestine. DXA analysis revealed slightly higher lean content in BSN birds compared to NC. These results showed that dietary supplementation of the BSN blend significantly improved broilers performance during the early NE challenge phase, as well as in the grower period.
Diminished satellite cell fusion and S6K1 expression in myotubes derived from skeletal muscle of low birth weight neonatal pigs
Chen, Ying; Zhu, Haibo; McCauley, Sydney R.; Zhao, Lidan; Johnson, Sally E.; Rhoads, Robert P.; El-Kadi, Samer Wassim (The American Physiological Society, 2017-02-09)
Low birth weight (LBWT) is consistently associated with impaired postnatal muscle growth in mammals. Satellite cell (SC)‐mediated myonuclear incorporation precedes protein accumulation in the early stages of postnatal muscle development and growth. The objective of this study was to investigate proliferation and differentiation of SCs and the regulation of protein synthesis signaling in response to insulin‐like growth factor (IGF)‐I stimulation in SC‐derived myotubes of LBWT neonatal pigs. SCs isolated from Longissimus dorsi muscle of LBWT and NBWT pigs (3‐d‐old, n = 8) were cultured and induced to proliferate and differentiate to myotubes in vitro. On day 3 of differentiation, myotubes were fasted in serum‐free media for 3 h and treated with human recombinant R³‐insulin‐like growth factor‐I (rh IGF‐I) at 0, 25, and 50 ng × mL⁻¹ for 30 min. There was no difference in proliferation rates of SCs from LBWT and NBWT pigs. However, LBWT SC fusion was 15% lower (P ≤ 0.05) without a difference in MyoD or myogenin mRNA expression in comparison with NBWT pigs, suggesting SCs are not intrinsically different between the two groups. IGF‐Ι stimulation at physiological concentrations activated downstream effectors of mTOR similarly in myotubes from LBWT and NBWT pigs. However, abundance of ribosomal protein S6 kinase 1(S6K1) was lower in myotubes of LBWT compared to their NBWT siblings (P ≤ 0.05). These results indicate that the modest reduction in SC fusion and S6K1 expression are not the major contributors to the impaired postnatal muscle growth of LBWT pigs.
Direct and correlated responses to selection for autumn lambing in sheep
Asadi-Fozi, Masood; Bradford, Heather L.; Notter, David R. (2020-10-02)
Background Seasonal reproduction limits productivity, flexibility, and profitability in commercial sheep production. Hormonal and (or) photoperiodic manipulation can be used to control estrous cycles in sheep and reduce limitations that are imposed by the seasonal anestrous but are often impractical or incompatible with the extensive management systems preferred for ruminant livestock. Thus, the current study investigated the use of selection to improve realized fertility (i.e., the proportion of ewes that lambed) following an out-of-season spring joining period (May and June) in a crossbred sheep population. Results Over 17 years, estimated breeding values (EBV) for fertility in selected (S) ewes increased by 0.175 (0.01 per year). The mean EBV for fertility of S ewes was greater than that of control ewes by year 10 (P = 0.02), and the fertility of adult (≥ 3 years old) ewes reached 0.88 ± 0.05 by year 17. Lambing began approximately 140 days after the introduction of rams, and 64% of the S ewes that lambed did so in the first 17 days of the potential lambing season, which indicated that most of the S ewes were cycling at the time of ram introduction and were not induced to cycle by the introduction of breeding males (i.e., the so-called “ram effect”). Animals in the S line had modest increases in body weight and scrotal circumference. A modest negative trend in the additive maternal effect on birth weight was observed but was reversed by additional selection on EBV for maternal birth weight. The heritability of litter size in autumn lambing was low (0.04) and could potentially limit the response to selection for this trait. Conclusions Selection improved realized ewe fertility in out-of-season mating, with absolute increases of approximately 1% per year in the percentage of joined ewes that lambed in the autumn. Genetic antagonisms with other performance traits were generally small. A modest antagonism with maternal breeding values for birth weight was observed but it could be accommodated by selection on EBV for maternal birth weight. Our results support results of previous studies that indicate that these selected ewes had one of the shortest seasonal anestrous periods reported for temperate sheep breeds and that spring-lambing lactating ewes from the selection line were capable of relatively rapid rebreeding in the spring.
Do not feed the wildlife: associations between garbage use, aggression, and disease in banded mongooses (Mungos Mungo)
Flint, Bonnie Fairbanks; Hawley, Dana M.; Alexander, Kathleen A. (Wiley, 2016-07-25)
Urbanization and other human modifications of the landscape may indirectly affect disease dynamics by altering host behavior in ways that influence pathogen transmission. Few opportunities arise to investigate behaviorally mediated effects of human habitat modification in natural host–pathogen systems, but we provide a potential example of this phenomenon in banded mongooses (Mungos mungo), a social mammal. Our banded mongoose study population in Botswana is endemically infected with a novel Mycobacterium tuberculosis complex pathogen, M. mungi, that primarily invades the mongoose host through the nasal planum and breaks in the skin. In this system, several study troops have access to human garbage sites and other modified landscapes for foraging. Banded mongooses in our study site (N = 4 troops, ~130 individuals) had significantly higher within-troop aggression levels when foraging in garbage compared to other foraging habitats. Second, monthly rates of aggression were a significant predictor of monthly number of injuries in troops. Finally, injured individuals had a 75% incidence of clinical tuberculosis (TB) compared to a 0% incidence in visibly uninjured mongooses during the study period. Our data suggest that mongoose troops that forage in garbage may be at greater risk of acquiring TB by incurring injuries that may allow for pathogen invasion. Our study suggests the need to consider the indirect effects of garbage on behavior and wildlife health when developing waste management approaches in human-modified areas.
Downregulated Translation Initiation Signaling Predisposes Low-Birth-Weight Neonatal Pigs to Slower Rates of Muscle Protein Synthesis
Chen, Y.; McCauley, Sydney R.; Johnson, Sally E.; Rhoads, Robert P.; El-Kadi, Samer Wassim (Frontiers, 2017-07-11)
Low-birth-weight (LBWT) neonates experience restricted muscle growth in their perinatal life. Our aim was to investigate the mechanisms that contribute to slower skeletal muscle growth of LBWT neonatal pigs. Twenty-four 1-day old male LBWT (816 ± 55 g) and normal-birth-weight (NBWT; 1,642 ± 55 g) littermates (n = 12) were euthanized to collect blood and longissimus dorsi (LD) muscle subsamples. Plasma glucose, insulin, and insulin-like growth factor-I (IGF-I) were lower in LBWT compared with NBWT pigs. Muscle IGF-I mRNA expression were lower in LBWT than NBWT pigs. However, IGF-I receptor mRNA and protein abundance was greater in LD of LBWT pigs. Abundance of myostatin and its receptors, and abundance and phosphorylation of smad3 were lower in LBWT LD by comparison with NBWT LD. Abundance of eukaryotic initiation factor (eIF) 4E binding protein 1 and mitogen-activated protein kinase-interacting kinases was lower in muscle of LBWT pigs compared with NBWT siblings, while eIF4E abundance and phosphorylation did not differ between the two groups. Furthermore, phosphorylation of ribosomal protein S6 kinase 1 (S6K1) was less in LBWT muscle, possibly due to lower eIF3e abundance. In addition, abundance and phosphorylation of eIF4G was reduced in LBWT pigs by comparison with NBWT littermates, suggesting translation initiation complex formation is compromised in muscle of LBWT pigs. In conclusion, diminished S6K1 activation and translation initiation signaling are likely the major contributors to impaired muscle growth in LBWT neonatal pigs. The upregulated IGF-I R expression and downregulated myostatin signaling seem to be compensatory responses for the reduction in protein synthesis signaling.
Early-Life Stress Induced Epigenetic Changes of Corticotropin-Releasing Factor Gene in Anorexic Low Body Weight–Selected Chicks
Xiao, Yang; Wang, Jinxin; Siegel, Paul B.; Cline, Mark A.; Gilbert, Elizabeth R. (MDPI, 2020-04-27)
The expression of neuropeptide Y (NPY) in the arcuate nucleus (ARC) and corticotropin-releasing factor (CRF) in the paraventricular nucleus (PVN) were increased when low body weight–selected (LWS) line chicks, which are predisposed to anorexia, were subjected to a combination of nutritional and thermal stressors at hatch. We hypothesized that such changes resulted from epigenetic modifications. We determined global DNA methylation, DNA methyltransferase (DNMT) activity, and methylation near the promoter regions of NPY and CRF, in the hypothalamus of LWS chicks on day 5 post-hatch. Stress exposure at hatch induced global hypermethylation and increased DNMT activity in the ARC but not PVN. In the PVN of stressed LWS chicks, there was decreased methylation of a CpG site located at the core binding domain of methyl cytosine binding domain protein 2 (MBD2), near the CRF gene promoter. We then demonstrated that this was associated with disrupted binding of MBD2. There was also reduced utilization of yolk reserves and lean and fat masses in chicks that were stress-exposed. These findings provide novel insights on molecular mechanisms through which stressful events induce or intensify anorexia in predisposed individuals and a novel molecular target for further studies.
The effects of dietary macronutrient composition on lipid metabolismassociated factor gene expression in the adipose tissue of chickens are influenced by fasting and refeeding
Wang, Guoqing; McConn, Betty R.; Liu, Dongmin; Cline, Mark A.; Gilbert, Elizabeth R. (BMC, 2017-05-10)
Background: Broiler chickens are compulsive feeders that become obese as juveniles and are thus a unique model for metabolic disorders in humans. However, little is known about the relationship between dietary composition, fasting and refeeding and adipose tissue physiology in chicks. Our objective was to determine how dietary macronutrient composition and fasting and refeeding affect chick adipose physiology during the early post-hatch period. Methods: Chicks were fed one of three isocaloric diets after hatch: high-carbohydrate (HC; control), high-fat (HF; 30% of ME from soybean oil) or high-protein (HP; 25% vs. 22% crude protein). At 4 days post-hatch, chicks were fed (continuous ad libitum access to food), fasted (3 h food withdrawal), or refed (fasted for 3 h and refed for 1 h). Subcutaneous, clavicular, and abdominal adipose tissue was collected for histological analysis and to measure gene expression, and plasma to measure non-esterified fatty acid (NEFA) concentrations (n = 6–10 per group). Results: Adipose tissue weights were reduced in chicks that were fed the HP diet and adipocyte diameter was greater in the adipose tissue of chicks that ate the HF diet. Consumption of diets differing in protein and fat content also affected gene expression; mRNAs encoding fatty acid binding protein 4 and a lipolytic enzyme, monoglyceride lipase, were greater in chicks fed the HC and HF than HP diet in all three adipose tissue depots. Fasting influenced gene expression in a depot-dependent manner, where most fasting and refeeding-induced changes were observed in the clavicular fat of chicks that consumed the HC diet. Fasting increased plasma NEFA concentrations in chicks fed the HC and HP diets. Conclusions: The decreased adipose tissue deposition in chicks fed the HP diet is likely explained by decreased rates of adipogenesis. Consumption of the HF diet was associated with greater adipose tissue deposition and larger adipocytes, likely as a result of greater rates of adipocyte hypertrophy. The depot-dependent effects of diet and fasting on gene expression may help explain mechanisms underlying metabolic distinctions among subcutaneous and visceral fat depots in humans.
Exposure to maternal obesity alters gene expression in the preimplantation ovine conceptus
McCoski, Sarah R.; Vailes, McCauley T.; Owens, Connor E.; Cockrum, Rebecca R.; Ealy, Alan D. (2018-10-11)
Background Embryonic and fetal exposure to maternal obesity causes several maladaptive morphological and epigenetic changes in exposed offspring. The timing of these events is unclear, but changes can be observed even after a short exposure to maternal obesity around the time of conception. The hypothesis of this work is that maternal obesity influences the ovine preimplantation conceptus early in pregnancy, and this exposure will affect gene expression in embryonic and extraembryonic tissues. Results Obese and lean ewe groups were established by overfeeding or normal feeding, respectively. Ewes were then bred to genetically similar rams. Conceptuses were collected at day 14 of gestation. Morphological assessments were made, conceptuses were sexed by genomic PCR analysis, and samples underwent RNA-sequencing analysis. While no obvious morphological differences existed between conceptuses, differentially expressed genes (≥ 2-fold; ≥ 0.2 RPKM; ≤ 0.05 FDR) were detected based on maternal obesity exposure (n = 21). Also, differential effects of maternal obesity were noted on each conceptus sex (n = 347). A large portion of differentially expressed genes were associated with embryogenesis and placental development. Conclusions Findings reveal that the preimplantation ovine conceptus genome responds to maternal obesity in a sex-dependent manner. The sexual dimorphism in response to the maternal environment coupled with changes in placental gene expression may explain aberrations in phenotype observed in offspring derived from obese females.
Fasting differentially alters the hypothalamic proteome of chickens from lines with the propensity to be anorexic or obese
Liu, Lingbin; Yi, Jiaqing; Ray, W. Keith; Vu, Lucas T.; Helm, Richard F.; Siegel, Paul B.; Cline, Mark A.; Gilbert, Elizabeth R. (Springer Nature, 2019)
Background: The hypothalamus is the ultimate modulator of appetite and energy balance and therefore sensitive to changes in nutritional state. Chicks from lines selected for low (LWS) and high (HWS) body weight are hypophagic and compulsive eaters, respectively, and differ in their propensity to become obese and in their hypothalamic mRNA response to fasting. Methods: As fasting-induced changes in hypothalamic proteins are unknown, we investigated the hypothalamic proteomes of 5-day old LWS and HWS chicks in the fed and fasted states using a label-free liquid chromatographytandem mass spectrometry (LC-MS/MS) approach. Results: A total of 744 proteins were identified in the chicken hypothalamus, and 268 differentially abundant proteins were identified among four pairwise comparisons. Ninety-five proteins were associated with the response to fasting in HWS chicks, and 23 proteins were associated with the response to fasting in LWS chicks. Fasting-responsive proteins in HWS chicks were significantly enriched in ATP metabolic processes, glyoxylate/dicarboxylate metabolism, and ribosome function. There was no enrichment for any pathways in LWS chicks in response to fasting. In the fasted and fed states, 159 and 119 proteins differed between HWS and LWS, respectively. Oxidative phosphorylation, citric acid cycle, and carbon metabolism were the main pathways associated with differences between the two lines of chicks. Enzymes associated with metabolic pathways differed between HWS and LWS in both nutritional states, including fumarase, aspartate aminotransferase, mitochondrial GOT2, 3-hydroxyisobutyrate dehydrogenase, chondrogenesis associated lipocalin, sialic acid synthase, arylamine N-acetyltransferase, pineal gland isozyme NAT-3, and succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial. Conclusions: These results provide insights into the hypothalamic metabolic pathways that are affected by nutritional status and the regulation of appetite and eating behavior.
Lamb performance in hardwood silvopastures, II: animal behavior in summer
Pent, Gabriel J.; Greiner, Scott P.; Munsell, John F.; Tracy, Benjamin F.; Fike, John H. (Oxford University Press, 2019-11-25)
Integrating trees into pastures, a practice known as silvopasture, may benefit livestock in the summertime through the provision of shade. The purpose of this project was to compare the behavioral patterns of sheep grazing in silvopastures and open pastures. Black walnut (Juglans nigra L.) and honeylocust (Gleditisia triacanothose L.) based silvopasture systems were compared with open pastures in a randomized complete block design with three blocks over two summers. Behavior measures were recorded within a replicate within a week, and these measures were taken sequentially within three experimental periods. Ewe lambs (n = 3) within each experimental unit were equipped with a wideband audio-recording device to detect prehension events. Time-lapse cameras documented sheep behavior every 60 s. In the silvopastures, the lambs spent over 90% of daylight hours within shade from trees. Lambs in silvopastures spent more time lying down than animals in the open pastures (P ≤ 0.01), while lambs in the open pastures spent more than 2 h longer each day standing (P < 0.0001). Lambs in the black walnut silvopastures spent more time grazing (488 ± 14 min · d⁻¹) than lambs in the honeylocust silvopastures (438 ± 14 min · d⁻¹; P = 0.0493) and lambs in the open pastures (417 ± 14 min · d⁻¹; P = 0.0026). There was no difference in grazing time for lambs in the latter two systems (P = 0.5597). Spectral analysis of the imagery revealed that the lambs in the black walnut silvopastures grazed more frequently than the lambs in the other systems for both years. The acoustic analysis, though limited by recorder durability to 47 complete recordings, revealed no difference in total bites taken per day (P ≥ 0.7222) or in the morning (P ≥ 0.2069), afternoon (P ≥ 0.5816), and evening periods (P ≥ 0.9337). Silvopastures provide an opportunity to improve lamb comfort in the summer.
Necrotic Enteritis in Broiler Chickens: The Role of Tight Junctions and Mucosal Immune Responses in Alleviating the Effect of the Disease
Emami, Nima K.; Calik, Ali; White, Mallory B.; Young, Mark; Dalloul, Rami A. (MDPI, 2019-07-31)
Necrotic enteritis (NE) continues to present major challenges to the poultry industry, and the etiologic agent Clostridium perfringens is the fourth leading cause of bacterially-induced food- borne illnesses in the US. This study was designed to evaluate the effects of a probiotic during naturally occurring NE. On day of hatch, 1080 Cobb 500 male broilers were randomly allocated to three groups (12 replicate pens/treatment, 30 birds/pen) including (1) negative control (NC): corn-soybean meal diet; (2) positive control (PC): NC + 20 mg virginiamycin/kg diet (0.450 kg Stafac^®20/ton); and (3) NC + PrimaLac (1.36 and 0.91 kg/ton from 1–21 and 22–42 days, respectively). One day (d) post placement, all birds were challenged by a commercial live oocyst coccidia vaccine as a predisposing factor to NE. Body weight and feed intake were measured at the onset of NE (d 8) and end of each feeding phase. On d 8, small intestines of two birds/pen were examined for NE lesions, and jejunum samples from one bird were collected for mRNA gene expression analysis of tight junction proteins, cytokines, and nutrient transporters. Data were analyzed using the JMP software and significance between treatments identified by LSD (p < 0.05). Compared to NC, supplementation of probiotic reduced d 1–42 mortality; however, PC was the only group with significantly lower mortality. Despite significantly improved feed conversion ratio (FCR) in PC and probiotic groups during d 1–42, average daily gain was only higher in PC (77.69 g/bird) compared with NC (74.99 g/bird). Furthermore, probiotic and PC groups had significantly reduced lesion scores in the duodenum and jejunum compared to NC. Expression of claudin-3 was higher, while expression of zonula occluden-2 tended (p = 0.06) to be higher in probiotic-supplemented birds compared to NC. Moreover, birds fed the probiotic diet had significantly higher expression of IL-10, IL-17, AMPK-α1, and SGLT1 mRNA compared to NC birds. The expression of PepT1 was higher for the probiotic-supplemented group compared to PC. IFN-γ expression was lower in PC compared to NC, while there was no difference between probiotic and NC. There were no differences in gene expression of sIgA, TNF-α, IL-1β, and IL-22 among treatments. Collectively, these data indicate that in a naturally occurring NE model, supplementation of a probiotic helps to improve FCR and reduce lesions, potentially due to the improvements in mRNA expression of tight junctions, cytokines, and nutrient transporters.
Pathogenesis and shedding of Usutu virus in juvenile chickens
Kuchinsky, Sarah C.; Frere, Francesca; Heitzman-Breen, Nora; Golden, Jacob; Vázquez, Ana; Honaker, Christa F.; Siegel, Paul B.; Ciupe, Stanca M.; LeRoith, Tanya; Duggal, Nisha K. (Taylor & Francis, 2021-01-01)
Usutu virus (USUV; family: Flaviviridae, genus: Flavivirus), is an emerging zoonotic arbovirus that causes severe neuroinvasive disease in humans and has been implicated in the loss of breeding bird populations in Europe. USUV is maintained in an enzootic cycle between ornithophilic mosquitos and wild birds. As a member of the Japanese encephalitis serocomplex, USUV is closely related to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV), both neuroinvasive arboviruses endemic in wild bird populations in the United States. An avian model for USUV is essential to understanding zoonotic transmission. Here we describe the first avian models of USUV infection with the development of viremia. Juvenile commercial ISA Brown chickens were susceptible to infection by multiple USUV strains with evidence of cardiac lesions. Juvenile chickens from two chicken lines selected for high (HAS) or low (LAS) antibody production against sheep red blood cells showed markedly different responses to USUV infection. Morbidity and mortality were observed in the LAS chickens, but not HAS chickens. LAS chickens had significantly higher viral titers in blood and other tissues, as well as oral secretions, and significantly lower development of neutralizing antibody responses compared to HAS chickens. Mathematical modelling of virus-host interactions showed that the viral clearance rate is a stronger mitigating factor for USUV viremia than neutralizing antibody response in this avian model. These chicken models provide a tool for further understanding USUV pathogenesis in birds and evaluating transmission dynamics between avian hosts and mosquito vectors.
Periconceptional Heat Stress of Holstein Dams Is Associated with Differences in Daughter Milk Production and Composition during Multiple Lactations
Brown, Britni M.; Stallings, John W.; Clay, John S.; Rhoads, Michelle (PLOS, 2015-10-23)
Heat stress at the time of conception affects the subsequent milk production of primiparous Holstein cows; however, it is unknown whether these effects are maintained across multiple lactations. Therefore, the objective of the current study was to examine the relationship between periconceptional heat stress and measurements of milk production and composition in cows retained within a herd for multiple lactations. National Dairy Herd Improvement Association data was obtained from Dairy Records Management Systems. Records included milk production data and milk composition data from over 75,000 and 44,000 Holstein cows, respectively, born between 2000 and 2010 in Florida, Georgia, and Texas. Conception dates were calculated by subtracting 276 d from the recorded birth date. Records for cows conceived within the months of June, July, and August were retained as heat stress conceived (HSC) cows; cows conceived within the months of December, January, and February were retained as thermoneutral conceived (TNC) contemporaries. Adjusted 305-d mature equivalent milk, protein percent and fat percent were evaluated with a mixed model ANOVA using SAS. Milk production was significantly affected by periconceptional heat stress. When a significant difference or tendency for a difference was detected between the HSC and TNC cows, the TNC produced more milk in all but one comparison. The advantage in milk production for the TNC cows over the HSC cows ranged from 82 ± 42 to 399 ± 61 kg per lactation. Alterations in fat and protein percentage were variable and most often detected in first lactations (first > second or third). Overall, the most striking result of this study is the consistency of the relationship between HSC and milk production. The nature of this relationship suggests that heat stress at or around the time of conception impairs cow milk yield throughout her lifetime.
The pivotal role of pyruvate dehydrogenase kinases in metabolic flexibility
Zhang, Shuai; Hulver, Matthew W.; McMillan, Ryan P.; Cline, Mark A.; Gilbert, Elizabeth R. (2014-02-12)
Metabolic flexibility is the capacity of a system to adjust fuel (primarily glucose and fatty acids) oxidation based on nutrient availability. The ability to alter substrate oxidation in response to nutritional state depends on the genetically influenced balance between oxidation and storage capacities. Competition between fatty acids and glucose for oxidation occurs at the level of the pyruvate dehydrogenase complex (PDC). The PDC is normally active in most tissues in the fed state, and suppressing PDC activity by pyruvate dehydrogenase (PDH) kinase (PDK) is crucial to maintain energy homeostasis under some extreme nutritional conditions in mammals. Conversely, inappropriate suppression of PDC activity might promote the development of metabolic diseases. This review summarizes PDKs’ pivotal role in control of metabolic flexibility under various nutrient conditions and in different tissues, with emphasis on the best characterized PDK4. Understanding the regulation of PDC and PDKs and their roles in energy homeostasis could be beneficial to alleviate metabolic inflexibility and to provide possible therapies for metabolic diseases, including type 2 diabetes (T2D).
Promotion of adipogenesis by neuropeptide Y during the later stages of chicken preadipocyte differentiation
Shipp, Steven L.; Cline, Mark A.; Gilbert, Elizabeth R. (2016-11)
Neuropeptide Y (NPY) promotes adipogenesis in both birds and mammals, although mechanisms in avians remain unclear. The objective of this study was thus to evaluate effects of NPY on chick preadipocyte proliferation and differentiation. Preadipocytes were treated with 0, 1, 10, or 100 nmol/L NPY and gene expression and cellular proliferation were evaluated at 12, 24, and 48 h. At 12 h posttreatment, mRNA abundance of topoisomerase II alpha (TOP2A), and thioredoxin-dependent peroxidase 2 was upregulated and NPY was downregulated in response to NPY (0 vs. 100 nmol/L) in preadipocytes. Cells were also treated with NPY during differentiation and harvested at 8, 10, and 12 days postinduction of differentiation. At day 8 postinduction of differentiation, there was increased lipid accumulation (0 vs. 10 and 100 nmol/L), expression of CCAAT/enhancer binding protein β and fatty acid binding protein 4 (FABP4) (0 vs. 100 nmol/L), and sterol regulatory element-binding protein (0 vs. 10 and 100 nmol/L) mRNA in NPY-treated cells. The number of proliferating cells decreased on day 8 in response to NPY (0 vs. 10 nmol/L). At day 10, FABP4 and Kruppel-like factor 7 mRNAs were downregulated (0 vs. 10 and 100 nmol/L, and 100 nmol/L, respectively), and at day 12, TOP2A mRNA was down-regulated (0 vs. 100 nmol/L) in response to NPY treatment. Activity of glycerol-3-phosphate dehydrogenase (G3PDH) was increased on days 10 and 12 in NPY-treated cells (0 vs. 100 nmol/L). Increased gene expression of proliferation markers in preadipocytes, and during differentiation increased expression of transcription factors and a fatty acid transporter, increased lipid accumulation, and increased activity of G3PDH suggest that NPY may enhance preadipocyte activity, adipogenesis, and promotes lipid accumulation throughout chicken adipocyte differentiation.

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