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Compensatory protein growth in swine
Doctoral Committee Chair(s)
Easter, Robert A.
Department of Study
Degree Granting Institution
University of Illinois at Urbana-Champaign
Agriculture, Animal Culture and Nutrition
A series of experiments were conducted to evaluate the effect of early nutrition on subsequent growth performance and protein gain. Compensatory body weight growth after a low quality starter feeding program was dependent on gender, genotype and feed intake. Pigs which had a good appetite exhibited the compensatory growth during late growing and finishing periods. The protein growth was compensated regardless of gender or genotype. Protein accretion is not diminished as much as fat deposition by feeding a low quality diet in the post-weaning period. Protein deposition is given priority over fat deposition. These experiments indicate that the lean gain for the entire production period was not affected by feeding and growth performance in the starter period.
Two experiments were conducted to determine the effect of protein deprivation on subsequent efficiency of dietary protein utilization and levels of blood urea nitrogen (BUN), insulin-like growth factor-I (IGF-I) and IGF binding protein (IGFBP)-3 to -1 and -2 ratio. Pigs fed a protein-deficient diet grew slower and less efficiently than those fed an adequate diet. Pigs fed a protein-deficient diet retained less nitrogen (N) and had lower IGF-I concentration and IGFBP ratio. However, they used dietary protein more efficiently when measured by lower BUN levels. Pigs previously fed a protein-deficient diet exhibited compensatory N retention during realimentation. The BUN level during the compensatory response was still lower indicating more efficient dietary protein utilization.
They also gained more body protein and water during the realimentation period regardless of feeding level or dietary crude protein. Compensatory protein growth requires a higher dietary protein concentration to maximize N retention and protein accretion. Blood urea nitrogen is a precise indicator of N retention and protein accretion efficiency while IGF-I levels and the IGFBP ratio are not good predictors of compensatory N retention.