Research On Protein Requirements Of Weaned Piglets

This single factorial designed experiment based on the effect of dietary protein levels on weaned piglets on growing performance ,diarrhea incidence,feces microflora , feed utilization,blood biochemical parameters and immune function to establish the appropriate dietary protein requirements on weaned piglets. Ninty(8.20±0.9 kg),(28±3 d) LY crossed weaning piglets were randomly allocated into five treatments(3 replicates per treatment,6 piglets per replicate),feeded with five graded levels of crude protein were 16.5%,17.6%,18.7%,19.8%,20.9%.The amino acid pattern and digestible energy in the five diets kept the same ,Dlys:D-SAA:DThr:DTrp=100﹕57﹕64﹕18.The period of experiment lasted 28 days in order to measure the average daily gain,average daily feed intake ,F/G and diarrhea incidence.After growth experiment,1 middle weight piglet in per replicate was picked out for bleeding to measure blood biochemical parameters and and immune function.Then, a healthy piglet was choosed for digestion trial ,in which apperant digestibility of dry matter ,crude protein and general energy can be measured.The results showed the range of CP level from 16.5% to 18.7%,average daily gain(ADG) and average daily food intake(ADFI) increased with increasing of CP level,but F/G decreased;CP level from 18.7% to 20.9%,ADG and ADFI decreased with further increasing of CP level,while F/G increased. ADG,ADFI and F/G changed with the elevated protein levels quadratically,when the crude protein level was 18.7%,the performance of piglets were best.Diarrhea frequency also changed with the protein levels quadratically,it was lowest in 18.7% and higherest in 20.9% protein group ,moreover,the diarrhea incidence in 20.9% protein group were significantly higher than those in other groups(p<0.01).The quantity of escherichia coli increased with the increasing of protein levels,in 20.9% protein group was signicantly higher than those in other groups(p<0.01).The apperant digestibility of dry matter ,crude protein and general energy increased with the increasing of protein level,from 18.7% protein level they began decreased.They changed with the protein level quadratically too.Serum Tp, AL,AL/GLO increased with the protein level increased and decreased in CP19.8% group, but there was no significant difference between CP19.8%group and CP 18.7% group(p>0.05);SUN concentration were not influenced by dietary protein levels(p>0.05).Cholesterol was lowest in 18.7% protein group than other groups,but in any two groups there was no significant(p>0.05).In 19.8% protein level , CPTand AST were higher than other groups,but as same as cholesterol,there was no significant in any two groups(p>0.05).IgG, IgA and IgM were not affected by the dietary protein level.