飼糧銅鋅含量對保育豬生長性狀與銅鋅代謝之影響以及與飼糧F-2毒素(zearalenone) 含量之相關

Abstract

Abstract Many piglet diets contain high levels of copper (Cu) and zinc (Zn) in order to reduce the incidence of digestive disorder and improve growth performance. Most of trace minerals ingested by piglets are not retained but excreted via feces and urine. Emission of trace minerals to the environment raises environmental pollution risks, especially for Cu and Zn. The problem can be reduced by appropriate inclusion of the minerals in the feed for piglets. Moreover, feed contaminated by Fusarium fungi may produce mycotoxins, for instance zearalenone (ZON), and lead to adverse effects on health and production of animals. High level of Cu and Zn in diets may be a way to reduce mycotoxin production from fungi. However, its efficacy needs of further confirmation. The aim of this study was to investigate the effect of rations containing low Cu and Zn levels on growth performance and metabolism of Cu and Zn for nursery piglets and to study their correlations to dietary ZON level. The results showed that dietary contents of 12 mg Cu/kg plus 60 mg Zn/kg or 24 mg Cu/kg plus 120 mg Zn/kg resulted in greater final body weight (P = 0.0063) and average daily gain (P = 0.0008) in growth trial. Feed conversion ratio (FC) and daily feed consumption (g/d) were not affected by dietary Cu and Zn levels in growth trial, but FC was greater (P = 0.0177) in pigs fed with 12 mg Cu/kg plus 60 mg Zn/kg containing diet and 12 mg Cu/kg plus 90 mg Zn/kg containing diet in metabolism trial. Varying dietary Cu and Zn levels resulted in no difference of serum Zn concentration but the highest serum Cu concentration resulted in pigs fed with 150 mg Cu/kg plus 140 mg Zn/kg at week two of the experiment. There were no differences in diarrhea score by varying dietary Cu and Zn contents. Other than that, there were no difference in the digestibilities of nutrients and balance of energy and nitrogen among the treatments of varying dietary Cu and Zn contents. The highest Cu was retention (mg/d) (P = 0.0001) in pigs fed 150 ppm Cu plus 140 ppm Zn containing diet. High Cu and Zn containing ration resulted in more fecal and urinary excretion of Cu and Zn when compared with low Cu and Zn containing rations. There was a negative correlation between dietary contents of Zn (mg/kg) and ZON (µg/kg) (r = -0.4692, P = 0.0319) indicating that Zn might be a mold inhibitor for reducing mycotoxin production and that might explain why ZON could not be detected in diet containing 150 mg Cu/kg plus 140 mg Zn/kg. In conclusion, dietary contents of 12 mg Cu/kg plus 60 mg Zn/kg or of 24 mg Cu/kg plus 120 mg Zn/kg may be the suitable levels for nursery piglets to support optimal growth and low excretion of Cu and Zn. Zinc may be a mold inhibitor to control mycotoxin production, which deserves more researches to confirm it.