Effects of corn type and fasting time before slaughter on growth and plasma index in weaning pigs1
A 2 × 2 factorial experiment was conducted to evaluate the effects of dietary corn type (waxy corn [WC] vs. nonwaxy corn [NC]) and fasting period (2 h vs. 12–16 h) before slaughter on growth and plasma index in weaning pigs. Twenty-four crossbred barrows (8.26 ± 0.47 kg) were allotted to 4 treatments with 6 replications of 1 pig per replicate metabolism cage. Waxy corn contained less fat, a lower amylase:amylopectin ratio, more CP, and more starch than NC. Pigs fed the WC diet had lower jejunum digesta pH compared with those fed the NC diet (P < 0.05). Maltase activity in the jejunum and ileum mucosa (P < 0.01), sucrose activity in the ileum mucosa (P < 0.01), and amylase activity in the pancreas and jejunum digesta (P < 0.05) were increased in pigs fed the WC diet relative to those fed the NC diet. But the total tract apparent digestibility (TTAD) of starch and CP was lower for the WC group (P < 0.05).Ingestion of the NC diet resulted in higher (P < 0.05) ADG and ADFI in the second week but did not affect ADG (P = 0.091) and the feed:gain ratio (F:G; P = 0.077) during the whole experiment period. The plasma glucose (P < 0.01) concentration was higher and high-density lipoprotein cholesterol (HDL-C; P < 0.01) concentrations was lower in the hepatic portal vein in pigs fed the WC diet relative to those fed the NC diet. Fasting 2 h before slaughter decreased the jejunum and ileum digesta pH compared with the 12-h fasting group (P < 0.01). Villus height increased in the duodenum (P < 0.01) and jejunum (P< 0.05) and the villus height:crypt depth ratio increased in the duodenum (P < 0.05) of pigs after shortening the fasting period before slaughter. Shortening the fasting time before slaughter resulted in higher plasma glucose (P < 0.05) concentrations and a higher HDL-C:low-density lipoprotein cholesterol (LDL-C) ratio (P < 0.05) whereas the LDL-C (P < 0.05) concentrations were reduced in the hepatic portal vein. The results of this experiment indicate that although the production performance of both WC and NC diets is equal, the glucose concentration is higher and HDL-C is lower in the portal vein for the WC diet, and fasting time before slaughter has an influence on the plasma index and intestinal morphology in weaning pigs。