| According to the uniform design Ug*(85), the experiment took crude protein(CP), lysine(Lys) and total phosphorus(TP) as three factors and set eight levels. The experiment was divided into10-30kg,30-60kg,60-90kg three phases based on physiological characteristics of Xiangcun black pig. In each stage, forty eight Xiangcun black barrows with approximate initial weight (10.08±0.49) kg,(30.07±0.73) kg and (59.96±0.83) kg were selected, which were randomly divided into eight treatment groups with six replicates per treatment group and one Xiangcun black pig per replicate. The study was conducted to study the nutrient requirement and nutritive physiological effects of dietary nuterents in Xiangcun black pig by determing related growth performance, carcass traits, meat quality, blood biochemical index, hormone, digestive enzyme activity, intestinal mucosal morphology and gene expression.The main results were as follows.Experiment1was conducted to study the quantitative relation model between the nutrient requirement and growth performance of Xiangcun black pig in different growth phases. The results showed that, except the TP requirement of Xiangcun black pig in30-60kg and60-90kg stage, requirement of three nutrient factors was lower than recommended requirement of China Feeding Standard of Swine. The best growth performance of Xiangcun black pig was obtained when the optimum combination of the three factors was CP17.18%, Lys0.90%, TP0.56%in10-30kg stage(ADG0.48kg/d,FCR2.58F/G), CP15.84%, Lys0.79%, TP0.52%in30-60kg stage (ADG0.68kg/d,FCR2.97F/G), CP13.74%,Lys0.68%, TP0.47%in60-90kg stage(ADG0.77kg/d,FCR3.60F/G). The experiment also showed that CP was the most important factor to ADG and Lys was the most important factor to FCR.Experiment2was conducted to study the effect of different dietary nuterents on the carcass traits and meat quality in Xiangcun black pig. The aim was to investigate the influence degree of different dietary nuterents on carcass traits and meat quality and optimum nutrient requirement (60-90kg) for the best carcass traits. The results showed that, the best carcass traits (dressing percentage72.50%, lean meat percentage56.40%, back fat thickness26.58mm, eye muscle area32.15cm2, ham percentage,28.70%) of Xiangcun black pig was obtained when the optimum combination of the three factors was CP15.60%, Lys0.61%, TP0.35%. The effect of different dietary nuterents on the carcass traits and meat quality in Xiangcun black pig showed a curvilinear even parabolaa chang. The interaction between three different dietary nuterents had great effect on carcass traits and meat components. The experiment also showed that CP was the most important factor to carcass traits and meat components, and Lys the most important factor to meat quality.Experiment3was conducted to study the correlation of different dietary nuterents on blood biochemical index and hormone in Xiangcun black pig. The aim was to investigate the influence degree of different dietary nuterents on blood biochemical index and hormone in different growth phases. The results showed that, in10-30kg stage the dietary CP level was very significantly positively correlated with the serum AST (P<0.01), significantly positively correlated with serum UREA (P<0.05); the dietary Lys level was significantly positively correlated with serum AST (P<0.05); the dietary TP level was very significantly negatively correlated with the serum AST (P<0.01), significantly negatively correlated with serum TC (P<0.05), significantly positively correlated with serum P (P<0.05).In30-60kg stage the dietary CP level was very significantly positively correlated with the serum TC and UREA (P<0.01), significantly positively correlated with the serum TP (P<0.05); the dietary Lys level was significantly negatively correlated with serum Ca (P<0.05); the dietary TP level was very significantly negatively correlated with the serum TC and TP (P<0.01). In60-90kg stage no significant partial correlation was observed between the dietary CP level and serum biochemical indices;the dietary Lys level was significantly negatively correlated with the serum Glu (P<0.05); the dietary TP level was significantly negatively correlated with the serum Ca (P<0.05). Comprehensive analysis of experimental results of different stages showed that the significant of influence between different dietary nuterents and blood biochemical index became weaker along with the growth of Xiangcun black pig.No significant partial correlation was observed between the dietary nuterents and serum hormone except that the dietary TP level was significantly negatively correlated with the serum T3(P<0.05). In10-30kg stage the dietary nuterents were positively correlated with the serum hormone except that the dietary Lys level was negatively correlated with the serum IGF-1; In30-60kg stage there were negative correlation between the dietary CP, TP level and serum INS, T3, T4, as well as between the dietary Lys level and serum T3, T4. The others showed a positive correlation basically; In60-90kg stage the dietary nuterents were negatively correlated with the serum GH, T4as well as between the dietary Lys level and serum INS. The others showed a positive correlation basically. Comprehensive analysis of experimental results of different stages showed that the positive correlation of influence between different dietary nuterents and hormone became weaker along with the growth of Xiangcun black pig.Experiment4was conducted to study the correlation of different dietary nuterents on digestive enzyme activity, intestinal mucosal morphology in Xiangcun black pig. The aim was to investigate the effect of different dietary nuterents on Digestive physiology. The results showed that, the dietary CP level was significantly positively correlated with trypsin (P<0.05), very significantly positively correlated with the sucrase in jejunum (P<0.05), not significantly correlated with other digestive enzyme. The influence extent of dietary nuterents on digestive enzyme were CP>Lys>TP on trypsin, TP>CP>Lys on amylopsin, Lys>CP>TP on pancrelipase, TP> CP>Lys on maltase in jejunum, CP>TP>Lys on sucrase in jejunum, CP>Lys> TP on maltase in ileum, Lys>TP>CP on sucrase in ileum.The dietary CP and TP level were significantly positively correlated with crypt depth in jejunum (P<0.05). The dietary Lys level was ignificantly positively correlated with villus height in ileum (P<0.05). The influence extent of dietary nuterents on intestinal morphology were CP>TP>Lys on villus height in duodenum, Lys>TP>CP on crypt depth in duodenum, CP>Lys>TP on crypt depth in jejunum, Lys>TP>CP villus height in ileum, Lys>TP>CP on crypt depth in ileum and the influence extent of dietary nuterents on villus height in jejunum were almost the same. Comprehensive analysis of experimental results showed that, digestive enzyme secretion and activity were increasing along with addition of nutrition, and CP was the most important factor to digestive enzyme. Increasing addition of nutrition was propitious to villous height as well as crypt depth decreased in duodenum and increased in jejunum.Experiment5was conducted to study the the relation between different dietary nuterents and the gene expression in Xiangcun black pig. The aim was to investigate the influence degree of different dietary nuterents on the growth performance and meat quality gene expression. The results showed that, IGF-1gene expression was very significantly positively correlated with ADG (P<0.01), significantly positively correlated with the total amino acid and flavor amino acid in lean (P<0.05), significantly negatively correlated with FCR (P<0.05). The values of the correlation coefficient showed that IGF-1gene was a important factor to growth performance and IGF-1gene expressive increased the amino acid in lean. No significant correlation was observed between H-FABP gene expression and the index of growth performance, carcass traits, meat quality. The values of the correlation coefficient showed that H-FABP gene was a important factor to fat deposition. MSTN gene expression was very significantly negatively correlated with lean meat percentage, eye muscle area, the total amino acid and flavor amino acid in lean (P<0.01), significantly negatively correlated with dressing percentage (P<0.05), significantly positively correlated with intramuscular fat (P<0.05). Comprehensive analysis of experimental results showed that, IGF-1was a important gene to growth performance; H-FABP was a important gene to fat deposition; MSTN was a important gene to lean and amino acid deposition.The dietary CP level was positively correlated with. IGF-1and negatively correlated with H-FABP and MSTN (P<0.05) in liver and longissimus muscle; The dietary Lys was positively correlated with ICF-1and H-FABP, and negatively correlated with MSTN; The dietary TP was positively correlated with ICF-1, H-FABP and MSTN.In conclusion, dietary nutrition factors influenced production performance of Xiangcun black pig in some ways such as blood biochemical index, hormone, digestive enzyme activity, intestinal mucosal morphology and gene expression. The best growth performance of Xiangcun black pig was obtained when the optimum combination of the three factors was CP17.18%, Lys0.90%,TP0.56%in10-30kg stage, CP.15.84%, Lys0.79%,TP0.52%in30-60kg stage, CP13.74%,Lys0.68%,TP0.47%in60-90kg stage. The best carcass traits of Xiangcun black pig was obtained when the optimum combination of the three factors was CP15.60%, Lys0.61%,TP0.35%in60-90kg stage. |
PDF Full Text Request