Studies On Optimum Protein Levels In Supplement Feed Of Lambs

The experiment was conducted to study effects of different level of proteinsupplement feed on production performance,nutrients utilization, nitrogen metabolismand serum biochemical indicator of lambs.The experiment using single factor random grouping design, selected36small-tailed han sheep and Dorper sheep hybrid generation lamb15day-old, whichwere randomly divided into3group,every group has12repeat and every repeat hasonly1. The three groups protein levels of supplement feed was16%(group I),18%(group II),20%(group III). Back-grounding7d, trial period35d. Results indicate:(1)The effect of different protein level in supplement feed on17～31year-oldlamb’s body weight was no significant(P>0.05), but the body weight of group II is thehighest. With the growth of age, in the38days, the weight of group II and group IIIare significantly higher than group I(P<0.05). In45～52days, the weight of group IIwas significantly higher than group I and group III (P<0.05). In average daily gain,the group II is the heighest in every stage. Especially in the2,4,5weeks, the averagedaily gain of group II was significantly higher than group III (P<0.05) and group I(P<0.01).(2)The effect of different protein level in supplement feed on the body indexeswas significant (P<0.05). The average daily growth of body height, body length, heartgrith and cannon translucent were II>III>I, and the average daily growth of bodyheight, body length and heart grith were highly significant differences between thethree groups (P<0.01). Compared with group I, the average daily growth of cannontranslucent of group II and III were significant higher (P<0.05).(3)The effect of different protein levels in supplement feed on nutrients apparentdigestibility was significant (P<0.05). The apparent digestibility of DM, GE, CP, CF,NDF and ADF were II>III>I, and compared with group I, the apparent digestibility ofgroup II and III was significant higher (P<0.05).The apparent digestibility of Ca wasIII>II>I, and compared with group I, the Calcium apparent digestibility of group IIand III was significant higher (P<0.05).(4)The effect of different protein levels in supplement feed on nitrogenmetabolism was significant (P<0.05). The contentration of feeding nitrogen, fecal nitrogen, urinary nitrogen and absorbed nitrogen were III>II>I. The contentration offeeding nitrogen and urinary nitrogen were highly significant differences between thethree groups (P<0.01). The contentration of fecal nitrogen and absorbed nitrogen ofgroup III was significant higher than group I (P<0.05).(5)The effect of different protein levels in supplement feed on serum biochemicalindices was significant (P<0.05). The contentrantion of TP, ALB and GLU of group IIwere highest, compared with group I was significant (P<0.05), but with group III wasno significant(P>0.05). The contentrantion of BUN of group III was significant higherthan group I and II (P<0.05); the contentrantion of GHO and TG of group I weresiginificant higher than group II and III (P<0.05); the contentrantion of ALP of groupII was significantly higher than group III (P<0.05) and group I (P<0.01); thecontentrantion of CK was II>III>I, and the group I was significant higher group II(P<0.05), but compared with group I was no significant(P>0.05).Under the condition of this study, the results showed that the optimum protein ofsupplement feed was18%.