Requirements Of Sulphur Amino Acids And Appropriate Ratio To Lysine For New Zealand Growing Meat Rabbit

The New Zealand growing meat rabbits were considered as the object of the research in this experiment. The objective of this experiment was to determin the optimum crude fiber (CF) and lysine (Lys) level based on certain level of the measured digestible energy (DE) by examining the growth performance of New Zealand growing meat rabbit. The experiment was conducted to study the requirements of sulphur amino acids and the appropriate ratio to Lys in certain level of the measured DE and Lys for New Zealand growing meat rabbit. In order to achieve this purpose, the effects of different amounts of dietary sulphur amino acids on growth performance,serum biochemical indicators and insulin-like growth factor Ⅰ (IGF-Ⅰ) concentration and the actual measured value of the dietary amino acid level were further examined. The significance of this study was that the results could provide some parameters and basis for the requirements of sulphur amino acids and improve the appropriate ratio to other amino acids for New Zealand growing meat rabbit in our country.The experiment was divided into the following three main test portion. Test Ⅰ mainly measured the DE of various feed ingredients by digestion experiments, and then the measured data could provide the basis of determining the DE of the feed for Test Ⅱ and Test Ⅲ. The relatively suitability DE, CF and Lys levels were determined in Test Ⅱ, based on the basis of actual measurement of various feed ingredients in Test Ⅰ. And then the measured data could provide the basis of determining the requirements of sulphur amino acids for Test Ⅲ. The requirements of sulphur amino acids were determined in certain level of the measured DE in Test Ⅲ, based on the suitability of DE, CF and Lys levels of Test Ⅰ and Test Ⅱ.Experiment1The determination of digestible energy of feed ingredientsThe experiment used the replacement method for the determination of DE of feed ingredients. A total of7240-day-old healthy New Zealand growing meat rabbits with average body weight of (904.17±50.87) g were randomly assigned to9groups (Basis, Corn, Soybean meal, Corn germ meal, Wheat bran, Rice bran, Unite bran, Peanut shells, Alfalfa powder) with8replicates in each group and each replicate contained1rabbit by gender and body weight. A rabbit was reared in a cage. There was a pretrial period of6days followed by an experimental period of6days.The results showed as follows:the DE values of corn, soybean meal, corn germ meal,wheat bran, rice bran, alfalfa powder, unite bran and peanut shells were respectively15.03MJ/kg,14.61MJ/kg,13.73MJ/kg,9.98MJ/kg,14.24MJ/kg,8.27MJ/kg,3.82MJ/kg and4.76MJ/kg,Experiment2The appropriate level of crude fiber and lysine for growing meat rabbitA5×3two factor completely randomized design was adapted. Rabbits were respectively fed the experimental dies containing11.00%,12.00%,13.00%,14.00%and15.00%CF levels and0.70%,0.80%,0.90%Lys levels. A total of120healthy New Zealand growing meat rabbits with average body weight of (1000.93±70.33) g were randomly assigned to15groups with8replicates in each group and each replicate contained1rabbit by gender and body weight. A rabbit was reared in a cage. Rabbits were fed twice a day during the experiment. Conventional breeding management and immune disinfection procedures, free feed and drinking water were adopted. There was a pretrial period of7days followed by an experimental period of28days. Rabbits were respectively weighed to fasting by replicate in the early morning of the beginning and the end day of the experimental period. The total amount of feed consumed of the whole experiment period were counted and the average daily feed intake (ADFI), average daily gain (ADG) and feed to gain (F/G) of each treatment were calculated.The results showed as follows:dietary CF level had extremely significant influence on ADFI, ADG and F/G of each treatment (P<0.01). The ADFI and ADG of each treatment were quadratically elevated which were first increased and then decreased with the increasing level of CF, while the F/G was quadratically elevated which were first decreased and then increased with the increasing level of CF. The optimum values of the growth performance were in14.00%CF levels, but there was no significant difference in13.00%CF level and14.00%CF level (P>0.05). Dietary Lys level had no significant influence on ADFI and F/G of each treatment (P>0.05), but dietary CF level had significant influence on ADG (P<0.05). The optimum values of the growth performance were in0.80%Lys levels, but there was no significant difference in0.80%Lys level and0.90%Lys level (P>0.05). The interaction of CF and Lys had no significant effects on ADG, ADFI and F/G (P>0.10). Based on the regression and analysis of variance results,14.00%CF level and0.80%Lys level were more appropriate to the stage of growing rabbits.Experiment3Requirements of sulphur amino acids and appropriate ratio to lysine for New Zealand growing meat rabbitA single factor completely randomized design was adapted. Rabbits were respectively fed the experimental diets containing0.50%,0.55%,0.60%,0.65%,0.70%,0.75%and0.80%sulphur amino acids. A total of112healthy New Zealand growing meat rabbits with average body weight of (954.24±55.61) g were randomly assigned to7groups with16replicates in each group and each replicate contained1rabbit by gender and body weight. A rabbit was reared in a cage. Rabbits were fed twice a day during the experiment. Conventional breeding management and immune disinfection procedures, free feed and drinking water were adopted. There was a pretrial period of7days followed by an experimental period of28days.Four rabbits of each group were selected to carry a heart blood collection at three days before the end of the experiment. And serum total protein (TP), albumin (ALB), serum urea nitrogen (BUN) and insulin-like growth factor-Ⅰ (IGF-Ⅰ) content were measured. Rabbits were respectively weighed to fasting by replicate in the early morning of the beginning and the end day of the experimental period. The total amount of feed consumed of the whole experiment period were counted and the average daily feed intake (ADFI), average daily gain (ADG) and feed to gain (F/G)of each treatment was calculated.The results showed as follows:1) dietary sulphur amino acids level did not significantly affect average daily feed intake (P>0.05). The dietary sulphur amino acids level had significant influence on average daily gain and feed to gain (P<0.05). The average daily gain had the maximum value and the feed to gain had the minimum value in the group with the diet containing0.65%sulphur amino acids.2) The contents of total protein and albumin in serum were not significantly affected by sulphur amino acids level (P>0.05). The dietary sulphur amino acids level had significant influence on serum urea nitrogen and insulin-like growth factor-Ⅰ contents (P<0.05). The serum urea nitrogen content had the minimum value and the insulin-like growth factor-Ⅰ content had the maximum value in the group with the diet containing0.65%sulphur amino acids.Based on the above analysis of the results, dietary sulphur amino acids suitable level were0.65%and the ratio of Lys and sulphur amino acids was1:0.76when diet DE, CF and Lys level were respectively10.87MJ/kg,14.00%and0.85%. However, the actual measured values of Lys and sulphur amino acids levels were respectively0.79%and0.61%, and the ratio of Lys and sulphur amino acids was1:0.77.