Use of expander cottonseed meal in broiler diets formulated on a digestible amino acid basis.

This experiment was designed to evaluate the use of expander cottonseed meal (CSM) in broiler diets formulated on a digestible amino acid basis and to determine the tissue distribution of gossypol enantiomers and their relationship to gossypol consumption. Gossypol is an antinutritional polyphenolic pigment found in cottonseed. A total of 800 1-d-old broilers (Arbor Acres) was randomly divided into 40 groups of 20 birds each and placed in a broiler house with wood shavings litter. The CSM was included in starter and grower diets at 0, 7, 14, 21, and 28% of the diet. Diets were formulated to have similar levels of digestible methionine and lysine as the 0% CSM control diet. At 21 d of age, five birds per pen were randomly selected for the determination of gossypol enantiomers in plasma, liver, heart, and breast muscle. Tissues were again collected at 42 d of age. Results of this experiment indicated that at 21 d of age cumulative body weight and feed-to-BW ratios of birds fed CSM diets were not significantly different from the control. By 35 d of age, feed-to-BW ratios of experimental birds fed the 28% CSM diet were significantly greater than the control birds, and by 42 d, BW were lower than those of the control group. Tissue concentrations of total, (+) and (-) gossypol increased linearly as the level of CSM increased. At 42 d, liver had the most gossypol with a ratio of 87% (+) gossypol to 13% (-) gossypol. Plasma contained 73% (+) gossypol and 27% (-) gossypol. Heart contained 45% (+) gossypol and 55% (-) gossypol. Breast muscle had the least gossypol. Results of this experiment indicated that expander solvent CSM could be fed to broilers at up to 21% of the total diet if amino acid digestibility was considered.

Tissue distribution of gossypol enantiomers in broilers fed various cottonseed meals.

Plasma and tissue concentrations of total, (+)- and (-)-gossypol were determined in broilers fed cottonseed meals (CSM) from eight oil mills (five expander solvent, two expeller, and one direct solvent). Free gossypol in the meals ranged from 0.033 to 0.180%, and total gossypol ranged from 0.974 to 1.459%. The (+)-enantiomer of gossypol varied from 53.8 to 61.3% of total gossypol. Eight CSM diets containing 28% CSM and a soybean meal control diet were fed to 162 1-d-old male broiler chicks during a 3-wk starter period. Concentrations of free gossypol in the CSM diets ranged from 92 to 504 microg/g, and total gossypol ranged from 2,626 to 4,085 microg/g. All diets were formulated with the same concentrations of digestible lysine and methionine and were fed ad libitum. At 21 d of age, there were no significant differences in body weights, feed conversions, or mortality of birds fed the CSM diets when compared to birds fed the soybean meal diet. Concentrations of (+)- and (-)-gossypol in plasma, liver, kidney, and muscle increased linearly as the level of free gossypol increased in the diets. Liver had the highest concentration of total gossypol (71.4 to 313.6 microg/g DM) followed by kidney (9.2 to 36.3 microg/g DM), plasma (3.0 to 14.6 microg/mL), and muscle (2.1 to 9.8 microg/g DM). The proportion of (-)-gossypol was higher in plasma (26.7%) and kidney (25.6%) than in muscle (19.1%) and liver (16.0%). Performance data from this study indicate CSM can be used successfully in chick starter diets at levels up to 28% when diets are formulated on a digestible amino acid basis.

Experimental prevention of bitterweed (Hymenoxys odorata) poisoning of sheep.

To examine the effects on bitterweed toxicity of dietary factors known to increase thiol concentrations in the body, 36 lambs were fed one of the following diets (12 lambs/diet) for a minimum of 9 days prior to bitterweed administration: diet 1, 10% crude protein; diet 2, 20% crude protein, 0.5% methionine, 0.5% sodium sulfate, and 1,102 IU of vitamin E/kg; and diet 3, diet 2 with 0.5% ethoxyquin hydrochloride added. Four lambs fed each diet were euthanatized prior to bitterweed administration (initial euthanasia group). Four lambs fed each diet were administered bitterweed (0.68% hymenoxon, air-dried basis) at a rate of 0.25% of live weight for 5 consecutive days. The remaining four lambs on each diet served as unchallenged controls. In the initial euthanasia group, diet 2 increased extracellular blood thiol concentrations (1.12 vs 0.94 mg of SH/d1, P less than 0.10), rumen fluid thiol concentrations (4.46 vs 1.88 mg of SH/d1, P less than 0.05), and liver thiol concentrations (263.6 vs 109.3 micrograms SH/g of wet wt, P less than 0.05), compared with diet 1. Ethoxyquin hydrochloride (diet 3) reduced blood thiol concentrations (0.94 vs 1.12 mg of SH/dl, P less than 0.10) and liver thiol concentrations (151.6 vs 263.6 micrograms of SH/g of wet wt, P less than 0.05), compared with diet 2. Kidney thiols were unaffected by treatments.(ABSTRACT TRUNCATED AT 250 WORDS)