Browsing by Author "Lindemann, Merlin D."

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    The effect of dietary vitamin E on the humoral and cell-mediated immune response of pigs housed at different environmental temperatures or weaned at various ages
    Bonnette, Edward Dwain (Virginia Polytechnic Institute and State University, 1988)
    A set of experiments were conducted to evaluate the antibody response, serum vitamin E level, cortisol concentration and performance of pigs weaned at three ages (21, 28 or 35 d) and fed diet containing either 11 or 220 IU/kg diet recommended level of vitamin E. Supplemental dietary vitamin E (220 IU) increased the concentration of serum vitamin E but, did not affect performance, cortisol concentrations or the antibody response. As weaning age increased, weekly performance increased linearly as did cortisol levels. Animals weaned at 35 d age had the largest primary antibody response, but this difference was not observed for the secondary response. A second set of experiments evaluated effects of four dietary vitamin E levels (11, 110, 220 and 550 IU/kg feed) on the humoral and cell-mediated immune response and performance of 4 wk old weanling pigs housed at one of two nursery temperatures (19 or 30°C). Performance was greater for pigs housed at 19°C compared with pigs housed at 30°C, but mitogen stimulation indices of white blood cells, plasma cortisol levels, and antibody titers were similar. Serum and liver vitamin E levels linearly increased with increasing dietary vitamin E level, but performance, cortisol, antibody levels and mitogen induced stimulation indexes were not affected by supplemental vitamin E levels. In the third experiment, sows fed a NRC level of vitamin E demonstrated little fluctuation in serum vitamin E concentration during a 5 wk lactation period. There was a high concentration of vitamin E in colostrum, followed by a sharp decrease in milk vitamin E concentration after the first week of lactation and remained constant for the next four weeks. Piglet serum was initially low in vitamin Eat 1 d of age but increased with time peaking about week 3. These experiments suggest that supplementing dietary vitamin E above the levels recommended by the NRC to baby pigs (which nursed sows fed NRC recommended levels of vitamin E) will not influence cell-mediated or humeral immune response, performance parameters or cortisol levels when pigs were weaned at various ages or exposed to environmental temperature changes.
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    Effect of Folic Acid Supplementation and Dietary Protein Level on Growth Performance, Serum Chemistry and Immune Response in Weanling Piglets Fed Differing Concentrations of Aflatoxin
    Wang, Ding; Lindemann, Merlin D.; Estienne, Mark J. (MDPI, 2020-10-09)
    Effects of folic acid and protein levels on growth and serum chemistry in pigs fed aflatoxin were determined in two experiments. Increasing aflatoxin (250 to 800 ppb) decreased (P < 0.05) weight gain and feed intake for both of the 35-day trials. In Experiment 1, increasing aflatoxin (0, 250, 500 ppb), increased linearly (P < 0.05) aspartate aminotransferase (AST), alkaline phosphatase (ALKP) and ɣ-glutamyl transferase (GGT). Folic acid (0, 2.0, 5.0, 12.5 ppm) increased linearly (P < 0.05) serum K, Ca, P, Mg, and AST with the largest effect observed at 12.5 ppm. Folic acid decreased (P < 0.05) blood urea nitrogen (BUN): creatinine and Na:K. In Experiment 2, aflatoxin (800 ppb) increased (P < 0.05) glucose and GGT, and decreased (P < 0.05) Na:K and albumin:globulin. Increasing protein from 15 to 18% elevated BUN: creatinine (P < 0.05), albumin: globulin (P < 0.05), albumin (P < 0.05) and ALKP (P < 0.05). Folic acid (2 ppm) elevated (P < 0.05) BUN, and interacted with both aflatoxin (P < 0.10) and protein (P < 0.05) on BUN. Adding folic acid to aflatoxin contaminated diets improved some measures of clinical chemistry in Experiment 1 but not traditional growth performance measures. The higher protein level reduced the effects of aflatoxicosis on growth.
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    Reassessment of bone parameters and evaluation of a bone biopsy technique for determining calcium and phosphorus status of swine from weaning to market
    Combs, Nadine Rae (Virginia Polytechnic Institute and State University, 1989)
    Three trials, involving 300 pigs were conducted to evaluate the effect of feeding 70 to 130% of the NRC recommended Ca/P levels from weaning to market weight on the relationships between measures of Ca/P status of postweaning swine, and to derive response surfaces relating diet and time effects to observed performance and bone characteristics. Pigs were slaughtered every 4 weeks following the start of the trials to obtain third and fourth metacarpals and metatarsals. Asymptotic response surfaces, relating the effects of dietary Ca/P level and time on test to the observed performance or bone characteristics were derived. The estimated lack of fit was significant for many criteria, although the magnitude of difference in fit appeared to be very small; therefore, the asymptotic response surfaces were found to reflect well the response of performance and bone criteria to dietary Ca/P levels of 70 to 130% of NRC recommendations over the period from weaning to market. The Ca/P level associated with 95 and 98% of maximum bone length, wet weight, radius and dry fat- free ash percentage of bones appeared to be the same or lower than that required to maximize body weight, average daily gain and feed intake; the performance criteria reached near maximum for Ca/P levels approximating the NRC recommendations. Bone wall thickness, cross—sectional area, bending and shear force, bending and shear stress, extracted weight of bone, and dry fat-free ash weight appeared to require higher Ca/P levels than recommended by NRC to reach 95 or 98% of maximum. Seventy-five pigs were biopsied at 4 week intervals, and a biopsy sample was also taken from 225 pigs at slaughter, to evaluate a bone biopsy procedure for use as a live-animal sampling method in swine nutrition studies. Biopsy cores from the live and the slaughter pigs were similar, indicating that repeated sampling of the live animal did not significantly alter the composition of the biopsy core. Biopsy core measures were significantly correlated with intact third and fourth metacarpal and metatarsal bone measures. Comparisons of the least squares means and standard errors of biopsy core and bone dry fat-free ash percentage indicated that the biopsy procedure may be more useful when NRC recommended or higher Ca/P levels are fed. There was strong indications, however, that use of the biopsy procedure warrants further consideration.