Effects Of Active Immunization Against Melatonin On The Growth Performance And Carcass Quality Of Growing Pigs

Melatonin(MT) is an indolamine synthesized and secreted in darkness mainly by the pineal gland. It affects various physiological functions such as antioxidation, immunization, endocrine and reproduction. This trial was conducted to evaluate the efficacy of active immunization against melatonin on the growth performance and carcass quality of growing pigs. Ten (Landrace × Largewhite) growing pigs with body weight of 20±1.5kg were allotted randomly to two groups by weight. Every group included five replicates of one pig each. Pigs of each group were injected every 14 days with bovine serum albumin (BSA) or melatonin conjugated to BSA respectively. Primary inoculation was on day 1 and booster inoculation were on day 15, 29 and 43. All pigs were slaughtered on day 117.The result showed antibody titers of treatment animals were significantly higher (P<0.01) compared with control pigs. In phase l(from day1 to day 57), the average daily weight gain (AE)G) of treatment animals was 8.69%( P=0.232)greater than that of control pigs, and average daily feed intake (ADFI) was 6.84% (P=0.525) higher for treatment animals. The digestibilities of crude protein(CP) and gross energy(GE) were increased by 2.15% (P=0.430) and 2.22% (P=0.170) respectively , but that of ether extract(EE) was decreased by 2.74% (P=0.524) for treatment group. Treatment with MT increased logissimus muscle area (LMA) by 36.2% (P<0.05) , backfat depth by 13.6 (P<0.32) , rate of leaf fat (RLF)by 34.6% (P<0.053) and rate of slaughter by 3.04%. The water loss (WL) of pork was 13.13% (P<0.10) higher in treatment pigs compared with control pigs. The marbling score(MS) of treatment pigs was decreased by 11.1% (P<0.33) .The pH of pork was lower in treatment pigs. Active immunization against melatonin had no effect on pork color. Active immunization against melatonin increased the content of maleic dialdehyde(MDA) in pork by 10.05% (P<0.56) .In conclusion , active immunization against melatonin tended to improve ADG, ADFI,and the digestibilities of CP and GE. Logissimus muscle area and rate of leaf fat were significantly increased, backfat depth and rate of slaughter tended to be increased. Meanwhile, the WL and the content of MDA of pork tended to be increased.