Effect Of Protein Source In Low Protein Diets On Growth Performance, Nitrogen Balance And Digestion Dynamics In Piglets

This experiment was conducted to investigate the effect of other protein source that soybean was replaced with on growth performance, blood biochemical indicators, nitrogen balance, digestion dynamics of piglets in low protein diets where crystal amino acids were added, which provided theoretical basis for increasing rate of nitrogen utilization, improving nitrogen deposit, decreasing the amount of soybean meal and nitrogen excretion.36 Duroc×Landrace×Yorkshire weaned barrows with similar weight(14.62±1.46kg) were allocated to four dietary treatments in a randomized complete block design and fed with diets whose protein source consisted of soybean meal, cottonseed meal, soybean-meal-cottonseed-meal and fishmeal, respectively. The preliminary period included 5 days and the formal period included 28 days.The results are shown below:1、cottonseed meal caused a significant difference on reduction of average final weight, average daily feed intake and average daily growth and increase of feed/growth(P<0.05). The final weight, average daily feed intake and average daily growth were lower and feed/growth was higher than soybean meal slightly without significant difference in soybean-meal-cottonseed-meal(P>0.05). The average final weight and average daily growth decreased significantly(P<0.05) and increased feed/growth ratio significantly(P<0.05)while there was no significant difference between fishmeal and soybean on average daily feed intake(P>0.05).2、The nitrogen in urine, urea in serum and nitrogen excretion of cottonseed meal were higher than others significantly(P<0.05)while the rate of nitrogen deposit was lower than the others(P<0.05). There was no significant difference between soybean-meal-cottonseed-meal and fishmeal in rate of nitrogen deposit. The rate of nitrogen deposit was higher(P<0.05) and nitrogen excretion was lower(P<0.05) in soybean-meal-cottonseed-meal than in soybean meal, which could reduce by 10.68% per day. 3、Different protein source caused a significant effect on digestion rate of digesta protein and content of amino acid in intestine. The peak of protein digestion rate of soybean meal appeared at the P-jejunum. The peak of protein digestion rate of cottonseed meal appeared at the anterior intestine and amino acids degraded by protein were absorbed. The maximum of protein digestion rate of fishmeal emerged in the ileum while the amino acids were not be able to be absorbed completely. The protein digestion rate of soybean-meal-cottonseedmeal-meal was high in the whole intestine and changed slightly, and the amino acids were released uniformly with a high amount of emancipation.