Effects Of Dietary Digestible Energy Concentration On Growth Performance, Meat Quality And Lipid Metabolism In Rongchang Roast Strain Sucking Pigs

Traditionally, Rongchang Roast Strain Sucking pigs are an ideal material for making high-quality roast suckling pigs, body fat content especially intramuscular fat (IMF) content is importantly associated with the various aspects of meat quality for roast suckling pig products. In order to obtain effective ways to improve body fat content and modify meat quality of Rongchang Roast Strain Sucking pigs, the study investigated the effects of dietary digestible energy concentration on growth performance, meat quality, lipid metabolism and related gene expression in muscle and fat tissues so as to find the suitable dietary digestible energy concentration for optimal growth performance and optimal meat quality, and provide the scientific and theoretical base for nutrition requirement of Rongchang Roast Strain Sucking pigs. A total of 72 healthy weanling piglets (average weight 4.95±0.78 kg) were allotted to 4 treatments with 3 replicates per treatment and 6 piglets per replicate. The piglets were fed with 4 diets formulated dietary DE concentrations of 3.20,3.40,3.60 and 3.80 Mcal/kg. After 28 d, growth performance, meat quality, lipid metabolism and related gene expression in muscle and fat tissues were measured. The results were as follows:(1) There was a significant quadratic relationship between average daily gain (ADG) and dietary DE concentration (P< 0.05). As dietary DE concentration increasing, the ratio of feed intake and gain (F/G) decreased linearly (P<0.05).(2) Increasing dietary DE concentration resulted in a linear increase of average back fat thickness and IMF content (P< 0.05). Cooking loss (P<0.05) and shearing force (P<0.01) decreased linearly as dietary DE concentration was increased. But dietary DE had no significant effects on other carcass and meat quality indexes.(3) Amino acids ananysis of longissimus muscle showed a linear and quadratic decrease (P< 0.05) in aspartic acid and proline acid content respectively as dietary DE concentration increasing. Increasing dietary DE concentration linearly increase methionine content. There was a quadratic effect detected between valine, isoleucine, lysine, delicious amino acid content and dietary DE concentration.(4) The concentration of total triglyceride (TG) and high-density lipoprotein cholesterol (HDL-c) in serum increased linearly (P<0.01) as dietary DE concentration was increased. However, there were no significant differences observed in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) and non-esterified fatty acid (NEFA) between groups (P>0.05). (5) Increasing dietary DE concentration resulted in a linear increase of MDH activity in LM (P<0.01), but there was no effect detected in LPL activity (P>0.05). Increasing dietary DE concentration linearly enhanced the expression of PPARy mRNA and LPL mRNA in fat tissue (P<0.01). But there were no significant effects observed for the expression of PPARy mRNA and LPL mRNA in muscle tissue (P> 0.05).According to all the datas above, dietary DE concentration affected growth performance, meat quality, lipid metabolism and related gene expression in muscle and fat tissues of Rongchang Roast Strain Sucking pigs to some extent. And the suitable dietary energy concentration for optimal growth performance and optimal carcass and meat quality were 3.60 Mcal/kg and 3.80 Mcal/kg respectively. Increasing dietary DE concentration can increase body fat deposition to modify carcass and meat quality of Rongchang Roast Strain Sucking pigs. The possible mechanism is that high dietary DE concentration promote the expression of PPARy mRNA and LPL mRNA in fat tissues.