Effects Of Dietary Energy And Protein Levels On Growth Performance Meat Quality And Serum Biochemical Indices In CRP Strain's Roast Sucking Pigs

The aim of the study was to investigate the effects of dietary energy and protein levels on growth performance,meat quality,serum biochemical indices,and endocrine hormone so as to find the optimal dietary energy and protein levels of China Rongchang Pig(CRP) Strain's Roast Sucking pigs.The experiment was designed by 2×3 factorrial arrangement with two energy levels(3.37,3.60 Mcal/kg) and three protein levels(16,18,20%).One hundred and twenty healthy weanling pigs(average weight 5.01±0.73 kg) were chosen in the experiment and allotted randomly to 6 groups.Each group had 4 replicates with 5 pigs per replicate.Piglets of all treatments were fed the same diet for 21 d Growth performance,meat quality,biochemical indexes of serum,endocrine hormones were measured.The results were as follows:(1) The results showed that dietary energy level affected significantly ADG (P=0.006) and G/F(P=0.03),and growth performance in high energy level was greater than low energy level.The dietary protein level affected significantly ADG, ADFI and G/F(P＜0.001),and growth performance in 18%CP group was greater than 16%and 20%groups.There was significant interaction between dietary energy and protein levels in ADG(P=0.021),and no significance was found in other growth performance.(2) The dietary energy level affected significantly the muscle total color matter(P=0.045),cooking loss(P=0.000),and muscle fiber density.No significance was found in pH and diameter.Meat quality in high energy level was greater than low energy level.The dietary protein level affected significantly the muscle cooking loss (P=0.009),and no significance was found in other meat quality.There was significant interaction between dietary energy and protein levels in muscle fiber diameter (P=0.000),density(P=0.006),total color matter(P=0.049) and cooking loss (P=0.011).(3) The dietary energy level affected significantly the muscle crude protein (P=0.000),and no significance was found in other compositions.The dietary protein level affected significantly the muscle crude protein(P=0.001) and intramuscular fat (P=0.004),and muscle crude protein and intramuscular fat in 18%group was greater than 16%and 20%groups.There was significant interaction between dietary energy and protein levels in muscle crude protein(P=0.000) and the contents of Ca (P=0.018).(4) The dietary energy level affected significantly the muscle aspartic acid (P=0.002),glutamic acid(P=0.002),reducing sugar(P=0.022) and hydroxyproline (P=0.012).Aspartic acid,glutamic acid,reducing sugar and hydroxyproline in low energy level was greater than high energy level.The dietary protein level affected significantly the muscle aspartic acid(P=0.002),glutamic acid(P=0.001) and hydroxyproline(P=0.000).Aspartic acid,glutamic acid in 18%group was greater than 16%and 20%groups,and hydroxyproline in 18%group was lower than 16%and 20%groups.There was significant interaction between dietary energy and protein levels in muscle glutamic acid(P=0.038) and glycine contents(P=0.000).(5) The dietary energy level affected significantly AST(P=0.004) and GLU (P=0.037),and no significance was found in other serum biochemicl indices.AST and GLU in low energy level was greater than high energy level,TP,GLO in high energy level was greater than low energy level.The dietary protein level affected significantly AST(P=0.001),TP(P=0.000) and ALB(P=0.034).AST,ALT and SUN in 18%group was lower than 16%and 20%groups.There was significant interaction between dietary energy and protein levels in ALT(P=0.000).(6) The dietary energy level affected significantly serum insulin(P=0.001),GH (P=0.030),leptin(P=0.012),T3(P=0.030) and T4(P=0.002).Insulin,T3 and T4 in high energy level was greater than low energy level.GH and leptin in low energy level was greater than high energy level.The dietary protein level affected significantly insulin(P=0.002),leptin(P=0.022),T3(P=0.016) and T4(P=0.005). There was no significant interaction between dietary energy and protein levels in endocrine hormone(P＞0.05).According to all the data above,the dietary energy and protein levels affected abviously the growth performance,meat quality,biochemical indexes and endocrine hormones in serum of China Rongchang Pig(CRP) Strain's Roast Sucking pigs,and optimal dietary DE and CP were 3.60 Mcal/kg and 18%respectively.