Effects Of Low Protein Diet Supplemented Lysine And Methionine On Growth Performance, Nutrient Digesitibility And Serum Biochemical Indices Of Sika Deer Fawns

Three experiments were conducted to investigate the effects of low crude protein diet supplemented methionine and lysine on growth performance, nutrient digestibility and serum biochemical indices of sika deer fawns. Experiment one was growth experiment, sixteen healthy male sika deer were randomly divided into 4 groups with 4 replicates per group and 1 sika deer per replicate, restricted feeding 4 diets. Experiment was divided into four periods: firstly, sika deer age at weaning, control group(groupⅠ) fed 16.28% crude protein(CP) based diet, and test groups fed 13.40 % CP diet with 0.23% Lys and 0(groupⅡ), 0.06%(groupⅢ), 0.12%(groupⅣ) Met, respectively; secondly in earlier winter, control group(groupⅠ) fed 16.63% CP)based diet, and test groups fed 13.40 % CP diet with 0.30% Lys and 0(groupⅡ), 0.10%(group Ⅲ), 0.20%(groupⅣ) Met, respectively; thirdly in later winter, group Ⅰ fed 16.52% CP based diet, and test groups fed 13.70 % CP diet with 0.30% rumen-protected Lys(RPL) and 0(groupⅡ), 0.08%(group Ⅲ), 0.16%(group Ⅳ) rumen-protected Met(RPM), respectively; fourthly age at growth, groupⅠfed 17.21% CP based diet, and test groups fed 13.83 % CP diet with 0.30% RPL and 0(groupⅡ), 0.08%(group Ⅲ), 0.16%(group Ⅳ) RPM, respectively;Experiment 2 and 3 were digestion and metabolism experiments, 4 sika deer were used in a 4×4 Latin square test, the diets of experiment 2 and 3 were same with the diets of weaning and growth periods in experiment respectively.The results indicated that:Sika deer age at weaning, no significant difference of ADFI, ADG and G/F of each group, but group Ⅳ similar with group Ⅰ(P>0.05); serum TP and ALB content of group Ⅰ were higher than group Ⅱ(P<0.05), GLU below group Ⅲ(P<0.05), the ALT greater than group Ⅲ(P<0.05), AST was higher than group Ⅲ and Ⅳ(P<0.05), AKP was greater than group Ⅱ and Ⅲ(P<0.05), and AST actively of group Ⅳ was lower than group Ⅱ(P<0.05), and then serum BUN content of group Ⅰ was higher than group Ⅳ(P<0.05); serum Lys and Ile contents of group Ⅰ were significantly higher than group Ⅱ(P<0.05), Arg and NH3 were higher than other groups(P<0.05), Cit was greater than group Ⅲ(P<0.05), while Met content of group Ⅱ was significantly higher than that group Ⅲ(P<0.05), Thr and His content were lower than other groups(P<0.05); CP digestibility of group Ⅰ was significantly higher than other groups(P<0.05), EE digestibility was lower than group Ⅱ(P<0.05); Met digestibility of group Ⅰ and Ⅳ was higher than group Ⅱ and Ⅲ(P<0.05), the digestibility of other amino acids(except Lys and Cys) of group Ⅰ were significantly higher than the experiments group(P<0.05); N intake of group Ⅰ was higher than group Ⅱ(P<0.05), the N absorbed and urine N emissions of group Ⅰ were significantly greater than group other groups(P<0.05); allantoin and total urine purine derivatives emissions of group Ⅰ were higher than other groups(P<0.05), and total PD emissions group Ⅱ was lower than Ⅳgroup(P<0.05), xanthine and hypoxanthine of group Ⅱ was lower than other groups(P<0.05); It is concluded that the suited Lys and Met added in the diet with 13.40% CP of sika deer age at weaning were 0.23% and 0.12%.In the earlier winter, the of ADG group Ⅱ was significantly lower than group Ⅰ(P<0.05), and G/F was higher than group Ⅲ and Ⅳ(P<0.05);Serum TP and ALB contents of group Ⅱ were significantly lower than other groups(P<0.05), and GLOB lower than group Ⅲ(P<0.05), while ALT and AST higher than group Ⅲ(P<0.05), then the contents of ALT and BUN of grpup Ⅰ were higher than other groups(P<0.05); Phe serum content of group Ⅰ was higher than group Ⅱ(P<0.05), Glu was greater than group Ⅳ(P<0.05), NH3 was higher than other groups(P<0.05), while Gly was lower than t other groups(P<0.05), and Gly and Tyr were lower than groupⅣ(P<0.05), and NH3 of group Ⅲ lower than group Ⅱ and Ⅳ(P<0.05), His is lower than other groups(P<0.05), Ser content of group Ⅲ and Ⅱ were lower than group Ⅳ(P<0.05),and Ile and Leu lower than group Ⅰ and Ⅳ(P<0.05); digestibility of DM, OM, CP of group Ⅰ were significantly higher than group Ⅱ and Ⅲ(P<0.05), EE digestibility was lower than group Ⅲ and Ⅳ(P<0.05), and DM, OM, CP, NDF and ADF digestibility of Ⅳ group of was higher than groupⅡ(P<0.05); Thr, Pro and Met digestibility of group Ⅰ were greater than group Ⅱ(P<0.05), Gly, Leu, Cys and Asp digestibility were higher than group Ⅱ and Ⅲ(P<0.05), but Met was lower than group Ⅳ(P<0.05), the other amino acids(except Lys, Ser and Ala) were significantly higher than other groups(P<0.05), and then digestibility of Cys, Ile, Leu, Val, Asp of group Ⅳ were greater than group Ⅱ(P<0.05), Gly was higher than group Ⅱ and Ⅲ(P<0.05); It is concluded that the suited Lys and Met added in the diet with 13.70% CP of sika deer during earlier winter were 0.30% and between 0.10% and 0.20%.During later winter, ADG of group Ⅱ was lower than group Ⅰ and Ⅳ(P<0.05), F/G was higher than the other groups(P<0.05); serum BUN group Ⅰ was greater than group Ⅲ and Ⅳ(P<0.05), GLU was higher than other groups(P<0.05), and ALT of group Ⅳ was higher than group Ⅰ and Ⅲ(P<0.05); serum contents of Gly and Ala of group Ⅰ was lower than group Ⅲ and Ⅳ(P<0.05), while serum Cit content of group Ⅲ was lower than other groups(P<0.05), Arg lower than group Ⅳ(P<0.05), and Asp below groupⅠ and Ⅱ(P<0.05), while Orn of group Ⅳ greater than group Ⅰ and Ⅱ(P<0.05), Lys higher than other groups(P<0.05), but Lys content of group Ⅲ below group Ⅰ(P<0.05); the digestibility of CP, EE of group Ⅳ was higher than group Ⅱ(P<0.05); Met digestibility of group Ⅳ was higher than other groups(P<0.05), Glu, Phe, Val, Ile and Leu greater than group Ⅱ(P<0.05), and Met of group Ⅲ higher than group Ⅰ and Ⅱ(P<0.05), and Glu digestibility of group Ⅰ and Ⅳ dwas higher than Ⅱ group(P<0.05); It is concluded that the suited RPL and RPM added in the diet with 13.77% CP of sika deer during later winter were 0.30% and 0.16%.Age at growth, ADG of group Ⅳ was significantly higher than groupⅡ(P<0.05);Content of serum ALB Ⅱ was significantly lower than other group(P<0.05), AST greater than group Ⅲ(P<0.05), BUN content of group Ⅱ and Ⅲ lower than group Ⅰ and Ⅳ(P<0.05); serum Arg of group Ⅲ was significantly lower than group Ⅱand Ⅳ(P<0.05), Phe and Cit below group Ⅰ(P<0.05), Lys, Orn, His were lower than other groups(P<0.05), Gly lower than group Ⅱ(P<0.05), and Lys content of group Ⅳ higher than group Ⅱ(P<0.05), Ser, Cit and Gly were higher than other groups(P<0.05), and Tyr of group Ⅱ was higher than other groups(P<0.05), and Sar greater than group Ⅰ and Ⅲ(P<0.05); digestibility of CP of group Ⅰ was significantly higher than group Ⅱ(P<0.05), ADF and P were higher than other groups(P<0.05), EE digestibility was higher than group Ⅱ and Ⅲ(P<0.05); Met digestibility of group Ⅰ and Ⅲ was significantly higher than group Ⅱ and lower than groupⅣ(P<0.05), the other amino acids(except Lys) of group Ⅰ were significantly higher than that of other groups(P<0.05); N intake, N absorbed and urine N emissions of group Ⅰ was higher than other groups(P<0.05), N utilization and apparent biological titer of groupⅠ and Ⅱ lower than groupⅢ and Ⅳ(P<0.05), and N retained of group Ⅲ and Ⅳ was higher than group Ⅱ(P < 0.05); It is concluded that the suited RPL and RPM added in the diet with 13.83% CP of sika deer age at growth were 0.30% and 0.16%.Unnecessary amino acid metabolic pathways and nutrient consumption were reduced, balance of amino acid metabolism were improved with lysine and methionine supplemented in the low CP diet, even though the digestibility of nutrients cannot achieve normal CP diet, but similar growth performance of sika deer fawns fed low CP diet compare with sika deer fed normal CP diet, at the same time the nitrogen emissions and environmental pollution were reduced. Therefore, amino acids added to low CP diets show high efficiency: they remain among the simplest ways for growth performance, while cutting down environmental waste and economic consumption.