Study On The Optimum Standardized Ileal Digestable Lysine Requirement In Gestation Rongchang Sows

Two experiments were conducted to determine the optimal standardized ileal digestible lysine(SID Lys)requirement in gestation Rongchang sows.In the first experiment, purebred Rongchang gilts(n=50) were used to evaluate the optimal SID Lys requirement. A total of 50 sows were allocated to one of five diets in a completely randomized block design within body weight. The experiment diets were formulated to contain 0.35%, 0.45%, 0.55%, 0.65%, 0.75% SID Lys, respectively. And all diets were formulated to contain 11.75MJ/kg of ME. After breeding, the daily feed intake for all sows were 1.5kg during early gestation(1~90d). All sows feed the same basic diet during late gestation(91~parturition) and lactating. The results show that, during early gestation(1~90d) Rongchang sows body weight changes and backfat thickness changes had a quadratic curve relationship with SID Lys levels,but there were not significantly influence(P>0.05) by diets SID Lys levels. Serum urea nitrogen levels(Y)were significantly influence by diets SID Lys levels(X) during early geatation(0.01<P<0.05), and there had a quadratic curve relationship with SID Lys levels : Y=12.571X2-14.889X+6.9424(R2=0.872) and according to the quadratic curve regression analysis, the optimal SID Lys level was 0.592%. Insulin levels(Y) were significantly influence by diets SID Lys levels(X) during early geatation(0.01<P<0.05), and there had a quadratic curve relationship with SID Lys levels: Y=-39.5X2+43.16X-0.9573(R2=0.752) and according to the quadratic curve regression analysis, the optimal SID Lys level was 0.546%. IGF-I levels(Y) were significantly influence by diets SID Lys levels(X) during early geatation(0.01<P<0.05), and there had a quadratic curve relationship with SID Lys levels: Y=-1540.7X2+1619.3X+73.693(R2=0.966), and according to the quadratic curve regression analysis, the optimal SID Lys level was 0.526%. Prolactin(Y) were singnificantly influence by diets SID Lys levels(X) during early gestation(0.01<P<0.05), and there had a quadratic curve relationship with SID Lys levels: Y=-450.5X2+513.48X+62.662(R2=0.728), and according to the quadratic curve regression analysis, the optimal SID Lys levels was 0.570%. Besides, average piglet birth weight and the serum biochemical indicators of piglet in lactating were singnificantly by SID Lys levels during early gestation(0.01<P<0.05).In summary, different evaluation index was obtained different optimum SID Lys during gestation 1~90d of Rongchang sows, and when the diet SID Lys levels is 0.529%~0.592% can play a better role of Rongchang sows’ reproductive performance.Experiment 2 was conducted to evaluate the optimum SID Lys requirement for Rongchang sows during late gestation(91~110d). Purebred Rongchang sows(n=55, Parity = 2) were allocated to one of five diets in a completely randomized block design within body weight. According the results of experiment 1 design diet for pregnancy sows during gestation 1~90d. The experiment diets during gestation 91~110d were formulated to contain 0.50%, 0.60%, 0.70%, 0.80%, 0.90% SID Lys, respectively. And all diets were formulated to contain 12.50MJ/kg of ME. After breeding, the daily feed intake for all sows were 1.5kg and the same basic diet during early gestation(1~90d). The daily feed intake for all sows were 2.0kg during late gestation(91~110d).When sows delivered, all sows feed the same basic diet. The results show that, backfat thickness changes were significantly influence(0.01<P<0.05) by diets SID Lys levels during late gestation(91~110d), piglets birth weight and sows’ body weight changes during lactation were significantly influence(0.01<P<0.05) by diets SID Lys levels during late gestation(91~110d), blood glucose, serum urea nitrogen levels were significantly influence(P<0.05) by diets SID Lys levels during early gestation(91~110d) and the serum urea nitrogen levels(Y) had a quadratic curve relationship with SID Lys levels(X): Y =16.714X2- 24.16 X + 10.496(R2=0.935), and according to the quadratic curve regression analysis, the optimal SID Lys levels was 0.723%. IGF-I(Y) were singnificantly influence by diets SID Lys levels(X) during late gestation 91~110d(0.01<P<0.05), and there had a quadratic curve relationship with SID Lys levels: Y=-1794.4X2+2650.4X-691.55(R2=0.980), and according to the quadratic curve regression analysis, the optimal SID Lys levels was 0.739%.Ins; free amino acid; progesterone; prolactin levels of gestation 110 d and piglets serum biochemical indexes were significantly influence(0.01<P<0.05) by diets SID Lys levels during late gestation(91~110d). In summary, different evaluation index was obtained different optimum SID Lys during gestation 91~110d of Rongchang sows, and when the diet SID Lys levels is 0.655%~0.723% can play a better role of Rongchang sows’ reproductive performance.