Browsing by Author "Watkins, Bruce A."

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    Bioavailability of phosphorus from various sources for young turkeys
    Potchanakorn, Manop (Virginia Polytechnic Institute and State University, 1988)
    Three series of experiments were conducted to determine the relative bioavailability of various phosphate products with an emphasis on the defluorinated phosphates. In Series I, phosphorus in commercial mono/dicalcium phosphates, commercial dicalcium phosphates, commercial defluorinated phosphates, and experimental defluorinated phosphates were found to be 93, 81, 70, and 76% as available as that in dicalcium phosphate dihydrate, respectively, using 3-week bodyweight and toe ash in a nonlinear regression analysis. In Series II, phosphorus in a commercial defluorinated phosphate was compared directly with that in a commercial dicalcium phosphate using poult from 1 to 4 weeks of age. No significant differences were found between the two products which may be attributed partly to the feeding of the starter diet during the pre-experimental period. The commercial defluorinated phosphate was numerically less available than the commercial dicalcium phosphate in all cases. In Series III, phosphorus in various defluorinated phosphates was compared with that in a dicalcium phosphate dihydrate. Ash of dry unextracted tibia, ash of dry toe, and 0 to 3-week body weight gain as responses to added phosphorus followed a sigmoidal regression model while 0 to 2-week body weight gain followed an asymptotic model in Experiment 1. The defluorinated phosphate was found to be 53% as available as the standard. In Experiment 2, an experimental defluorinated phosphate from Series I which was found to be 76% as available as the standard was found to be 62% as available as the standard used in Series III, indicating differences in bioavailability of the two standards. In Experiment 3, two commercial defluorinated phosphates were found to have equal relative biological values, 67.2 and 67.6% as compared with the standard using poults from 0 to 2 weeks of age, and three experimental defluorinated phosphates 51.7, 74.0, and 88.2% with the product with the fine particles having the highest relative biological value. In cases where the sigmoidal regression gave a significantly better fit to the data than the asymptotic model, the relative biological values and the associated confidence limits from the asymptotic model were equal to those from the sigmoidal model.
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    The effect of early feed restriction on the performance, organ weights, carcass composition, and lipid and protein metabolism in broiler chickens
    Fontana, Eddy Alejandro (Virginia Tech, 1991-05-05)
    Five experiments were conducted to investigate the effects of early feed restriction on body weights, feed conversion, organ weights, fat deposition, carcass and muscle composition, plasma lipids, lipogenesis, lipolysis, and muscle tissue DNA and RNA in broiler chickens. In Experiments 1 and 2, broiler chicks were reared in litter pens for 49 days, while Experiments 3,4, and 5 were conducted in battery cages for 28 days. Feed restriction in all experiments was induced by providing male broiler chicks with 40 kcal/bird/day for 7 (Experiments 1 and 2) or 6 (Experiments 3, 4, and 5) days, starting at 4 days of age. Feed restriction (40 kcal/bird/day) for broiler females in Experiment 1 was imposed from 4 to 9 days of age. Ad libitum feeding was resumed after the restriction periods and continued to the conclusion of each experiment. Broilers fed ad libitum for the entire experimental period were used as controls in each study. Broilers under early feed restriction had significantly (P s .05) lower mean body weights than ad libitum fed controls, for all ages measured. However, feed to gain ratios for restricted birds were Significantly lower at 28 (Experiments 1 through 4) and 49 (Experiments 1 and 2) days of age than for birds fed ad libitum. Total pen body weights for restricted and ad libitum fed groups were similar at 49 days of age in Experiments 1 and 2 which, reflected a significant reduction in the rate of mortality observed in the early restricted groups. Significantly higher levels of lipogenic activity, plasma triglycerides and lipoproteins (VLDL + LDL), and significantly larger abdominal fat pads were observed in restricted broilers than in ad libitum fed controls at 28 days of age (Experiment 4). No significant differences were found in organ weights, carcass composition, lipolysis, and muscle tissue DNA/RNA levels, and muscle composition between early restricted and unrestricted broilers. Results from these studies indicate that restricted broilers were not able to attain body weights comparable to ad libitum fed birds at 49 days of age. In contrast, early feed restriction resulted in consistently better feed efficiency in restricted birds when compared to controls. Furthermore, it appears that early feed restriction altered lipid metabolism early in life; however, organ weights, fat deposition, muscle composition, and carcass composition were only minimally affected by this procedure.
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    Evaluating fish meal as a protein source for lactating dairy cows
    Spain, James Nobles (Virginia Polytechnic Institute and State University, 1989)
    A series of experiments were conducted to measure the mode of action by which fishmeal exerts its effect on milk composition of dairy cows. Production Study One measured the effect of increased fishmeal intake on milk production and milk composition in dairy cattle. Milk fat percentage and yield were decreased by increased fishmeal intake. This decrease was not associated with changes in ruminal fermentation patterns. Plasma long-chain n-3 polyunsaturated fatty acids were increased with increased fishmeal intake. Mammary slices from lactating bovine mammary gland were incubated with eicosapentaenoic acid. Changes in ¹⁴C-acetate metabolism were measured. Acetate oxidation and incorporation into milk lipid were not changed by eicosapentaenoic acid. However, tissue from mammary gland of cows milked 6 to 8 h prior to slaughter had 2 fold higher activity than tissue milked 1 h before slaughter. Disappearance of dry matter, crude protein, and lipid in fish meal from undegradable bags in the rumen was measured. Dry matter and crude protein degradation of fish meal were similar to published values. Lipid escaped rapidly with greater than 70% removed by 8 h. A subsequent fish oil infusion study revealed that intraruminal fish oil treatment did not significantly alter ruminal fermentation, or change fatty acid profiles in duodenal digesta, plasma, or milk. Duodenal infusion increased plasma concentrations of n-3 fatty acids but did not affect milk lipid fatty acid composition. A second production study compared the effects of fish meal versus fish oil on milk production and composition, and changes in fatty acids in plasma and milk. Fish meal significantly increased plasma n-3 fatty acids compared to the fish oil treatment. Residual fatty acids contained in fish meal seemed to be protected from rumen degradation and probably remained intact for digestion and absorption since plasma n-3 fatty acid concentrations increased. No changes in milk yield or composition were due to the experimental treatments. Fat in fish meal and fish oil source differed significantly in their ability to alter milk composition and plasma fatty acid profiles.
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    Exerkines, Nutrition, and Systemic Metabolism
    Watkins, Bruce A.; Smith, Brenda J.; Volpe, Stella L.; Shen, Chwan-Li (MDPI, 2024-01-30)
    The cornerstones of good health are exercise, proper food, and sound nutrition. Physical exercise should be a lifelong routine, supported by proper food selections to satisfy nutrient requirements based on energy needs, energy management, and variety to achieve optimal metabolism and physiology. The human body is sustained by intermediary and systemic metabolism integrating the physiologic processes for cells, tissues, organs, and systems. Recently, interest in specific metabolites, growth factors, cytokines, and hormones called exerkines has emerged to explain cooperation between nutrient supply organs and the brain during exercise. Exerkines consist of different compounds described as signaling moiety released during and after exercise. Examples of exerkines include oxylipin 12, 13 diHOME, lipid hormone adiponectin, growth factor BDNF, metabolite lactate, reactive oxygen species (ROS), including products of fatty acid oxidation, and cytokines such as interleukin-6. At this point, it is believed that exerkines are immediate, fast, and long-lasting factors resulting from exercise to support body energy needs with an emphasis on the brain. Although exerkines that are directly a product of macronutrient metabolism such as lactate, and result from catabolism is not surprising. Furthermore, other metabolites of macronutrient metabolism seem to be candidate exerkines. The exerkines originate from muscle, adipose, and liver and support brain metabolism, energy, and physiology. The purpose of this review is to integrate the actions of exerkines with respect to metabolism that occurs during exercise and propose other participating factors of exercise and brain physiology. The role of diet and macronutrients that influence metabolism and, consequently, the impact of exercise will be discussed. This review will also describe the evidence for PUFA, their metabolic and physiologic derivatives endocannabinoids, and oxylipins that validate them being exerkines. The intent is to present additional insights to better understand exerkines with respect to systemic metabolism.
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    Saturation and isomerization of dietary fatty acids influence nutrient adsorption and metabolism in the chicken
    Brown, Patrick K. (Virginia Tech, 1991-07-07)
    Three experiments were conducted to contrast the effect of dissimilar lipid sources on broiler chicken metabolism. In Experiment 1, the nitrogen-corrected apparent metabolizable energy values (AMEn) of soybean oil (SBO) and hydrogenated soybean oil (HSBO) were determined. Trans monoenes, present only in HSBO, comprised 41% of total fatty acids. The AMEn contents of SBO and HSBO were determined to be 8,739 and 7,657 kcal/kg, respectively. The influence of dietary fatty acids on the lipid composition of the intestinal brush border membrane (BBM) was studied in Experiment 2. Beginning at hatch, chickens were provided isocaloric diets, identified as being either a minimal-lipid (1% 18:2n6) basal diet (ML) or one of three diets in which one-sixth of the caloric content of the basal diet was replaced by oils high in either polyunsaturates (HP), saturates (HS), or trans (HT) monoenes. The BBM alkaline phosphatase specific activity was greater in chickens fed HT than in those fed ML, HP, and HS. The BBM concentrations of palmitic, stearic, and oleic acids were not affected by treatment. Less linoleate (P<.06) and linolenate (P<.05) were present in the BBM of chickens receiving HT and HS than in those fed ML and HP. Arachidonate was present in greater concentrations when birds were fed ML, HP, and HS than when fed HT. Trans isomers were present only in the BBM from chickens fed HT. In Experiment 3, the effects of supplemental dietary lipidS on 1) the lipid composition of intestinal tissue and 2) the in vitro absorptive rate of differing dietary nutrients were studied. Diets similar to those in Experiment 2 were offered to broiler chicks from hatch to 28 days of age. Intestinal membrane concentrations of palmitic and oleic acids were not affected by dietary treatment. Chickens receiving the HSBO or the palm oil diet had less intestinal 18:0, 18:2n6, 18:3n3, and 20:4n6 than did those offered SBO or the control diet. In all treatments, linoleate and oleate were absorbed at a faster rate than stearate across all treatments. The in vitro uptake rates of oleate and linoleate were not affected by dietary treatment. Stearate and glucose uptakes were reduced in chickens fed HSBO or palm oil compared to those offered either the control diet or SBO diet.