Effects of different sources and levels of dietary gossypol on gossypol residues in plasma and milk of lactating cows.
Free gossypol residues in tissues or milk from feeding whole cottonseed and cottonseed meal were measured for their effect on health of dairy cows and humans. Forty lactating cows were randomly assigned to 5 treatments in a 60-d experiment to investigate the effects of sources and dietary level of gossypol on plasma and milk gossypol concentrations in lactating cows. Five experimental diets had identical net energy for lactation and crude protein content on a dry matter (DM) basis. Soybean meal was the main protein ingredient used in the control diet. Cottonseed meal (CSM) or whole cottonseed (WCS) substituted for part of the soybean meal in the other 4 diets. Gossypol levels in the 5 diets were 0 (control), 91.15 mg/kg of DM in CSM1, 117.31mg/kg of DM in CSM2, 385.43 mg/kg of DM in WCS1, and 611.13 mg/kg in WCS2. Yields of 3.5% fat-corrected milk were significantly higher for cows in the WCS2 group; cows in the CSM1 and WCS1 groups showed no differences but both were numerically higher than the control and CSM2 groups. Milk protein concentration was lower for cows consuming WCS1 compared with the control group. Lactose concentration was lower for cows in the CSM2 group compared with the WCS2 group, but no differences were observed among other diets. Aspartate aminotransferase in serum was significantly higher for the WCS2 group compared with the control and WCS1 groups, but no difference was observed with the CSM1 and CSM2 groups. Concentrations of gossypol in plasma and milk of cows in the WCS1 and WCS2 groups were both higher than those of the other groups. No adverse effects were observed on cows fed diets containing 12.0% CSM, and no gossypol was found in plasma and milk. When WCS comprised 15% of the diet DM, yields of 3.5% fat-corrected milk were increased in cows and gossypol was detected in plasma and milk but not at harmful levels.
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China; College of Animal Science and Technology, Hunan Agriculture University, Changsha, Hunan Province, 410128 China.
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AP
Wang
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China. Electronic address: zhjmxms@sina.com.
J M
JM
Zhang
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.
Y L
YL
Meng
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.
L Q
LQ
Deng
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China; College of Animal Science and Technology, South China Agricultural University, Guangzhou, Guangdong Province, 510642 China.
Y F
YF
Lv
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.
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C
Li
State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China.
J Q
JQ
Wang
D000821:Animal Feed; D000818:Animals; D001219:Aspartate Aminotransferases / Q000097:blood; D002417:Cattle; D003369:Cottonseed Oil / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000378:metabolism; D004350:Drug Residues / Q000032:analysis*; D005260:Female; D006072:Gossypol / Q000032:analysis / Q000097:blood / Q000493:pharmacokinetics*; D007774:Lactation / Q000378:metabolism; D007785:Lactose / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis
D003369:Cottonseed Oil; D004044:Dietary Proteins; D008894:Milk Proteins; D001219:Aspartate Aminotransferases; D007785:Lactose; D006072:Gossypol