Comparison of the efficacy of gossypol acetate enantiomers in rats with uterine leiomyoma.

Gossypol acetate (GA), as the product of racemic gossypol and acetic acid conjugated by hydrogen bond, is hydrolyzed into gossypol to exert its effect on treating uterine leiomyoma (UL), which has been listed in China. But hypokalemia and mild changes of liver function limit its clinical application. It had been reported that the biological activities of gossypol optical isomers were different. In this study, we aimed to clarify whether there were differences in the efficacy of gossypol enantiomers and whether a single gossypol optical isomer could alleviate adverse reactions in the treatment of UL. The results indicated that (-)-GA and (+)-GA had significant therapeutic effect on rats with UL. Interestingly, (-)-GA could better significantly ameliorate the pathological structure, inhibit the secretion of estrogen, and downregulate the expression of estrogen receptor-alpha (ER-α) and progesterone receptor (PR) than (+)-GA. Additionally, (-)-GA could better evidently decrease the symptoms of abnormally elevated inflammatory factors caused by UL. In contrast, (-)-GA and (+)-GA had certain effects on potassium ion concentration in serum, liver and kidney function, and the effects of (+)-GA on liver function were more obvious than (-)-GA. These findings will be of great significance to the drug development of gossypol optical isomers.

Regulation of Cell Viability and Anti-inflammatory Tristetraprolin Family Gene Expression in Mouse Macrophages by Cottonseed Extracts.

Bioactive plant extracts have been used for the prevention and treatment of various diseases. One of the major classes of bioactive compounds is plant polyphenols. Cottonseed ethanol extracts were determined by HPLC-MS analysis to be essentially free of toxic gossypol. The objective of this study was to investigate the effect of cottonseed ethanol extracts on the cytotoxicity and regulation of anti-inflammatory tristrataprolin (TTP) family gene expression in mouse cells. MTT, qPCR and immunoblotting assays tested the effects of cottonseed extracts in mouse RAW264.7 macrophages and 3T3-L1 adipocytes. No cytotoxicity effect was observed in macrophages treated with extracts from the coat or kernel of glanded and glandless cottonseed. Similarly, the viability of mouse adipocytes was not affected by cottonseed extracts. In contrast, gossypol and lipopolysaccharides were toxic to macrophages but not adipocytes under high concentration or long time treatment. Cottonseed extracts exhibited modest effect on TTP family gene expression in macrophages but glandless cottonseed coat extract significantly increased TTP mRNA and protein levels with a magnitude similar to cinnamon and green tea polyphenol extract and insulin. These results demonstrated that cottonseed extracts are harmless towards the mouse cells and that glandless cottonseed coat extract stimulates TTP gene expression. We propose that glandless cottonseed is a safe source of plant polyphenols with anti-inflammatory property.

The Ameliorating Effect of Berberine-Rich Fraction against Gossypol-Induced Testicular Inflammation and Oxidative Stress.

This study was aimed at evaluating the efficacy of berberine-rich fraction (BF) as a protective and/or a therapeutic agent against inflammation and oxidative stress during male infertility. Sexually mature Sprague-Dawley male rats were divided into five groups treated with either corn oil, BF (100 mg/kg BW, orally, daily for 30 days), gossypol acetate (5 mg/kg BW, i.p.) eight times for 16 days, BF alone for 14 days then coadministered with gossypol acetate for the next 16 days (protected group), or gossypol acetate for 16 days then treated with BF for 30 days (treated group). All animals completed the experimental period (46 days) without obtaining any treatments in the gap period. Sperm parameters, oxidative index, and inflammatory markers were measured. Gossypol injection significantly decreased the semen quality and testosterone level that resulted from the elevation of testicular reactive oxygen and nitrogen species (TBARS and NO), TNF-α, TNF-α-converting enzyme, and interleukins (IL-1ß, IL-6, and IL-18) by 230, 180, 12.5, 97.9, and 300%, respectively, while interleukin-12 and tissue inhibitors of metalloproteinases-3 were significantly decreased by 59 and 66%, respectively. BF (protected and treated groups) significantly improved the semen quality, oxidative stress, and inflammation associated with male infertility. It is suitable to use more advanced studies to validate these findings.

Metabolic Characterization of Dairy Cows Treated with Gossypol by Blood Biochemistry and Body Fluid Untargeted Metabolome Analyses.

To characterize the metabolic disorders of dairy cows treated with gossypol, 12 dairy cows were assigned to either a control group or a treatment group that was fed 1000 mg of gossypol per kilogram of dry matter feed for 28 days. Milk quality was adversely affected, as both milk protein and lactose levels were significantly decreased in the gossypol-treated group (3.40% vs 3.16%, P = 0.044; 5.15% vs 4.91%, P = 0.027; respectively). Plasma samples revealed increases in alanine aminotransferase (P = 0.092), choline esterase (P = 0.02), and glutathione transferase (P = 0.0005) and decreases in glucose (P = 0.076) in the gossypol-treated group. Mass spectrometry based comparative metabolomic analyses showed reduced concentrations of the gluconeogenesis precursor l-glutamine (P = 0.047), with significant decreases (P < 0.05) in plasma l-lysine, l-threonine, and homoserine levels after gossypol treatment. HDL-C and LDL-C levels in the gossypol-treated group were increased (P = 0.044) and decreased (P = 0.023), respectively. These results demonstrate that gossypol induced oxidative stress and hepatotoxicity; reduced peripheral lipid metabolism, and enhanced hepatic lipid accumulation; decreased amino acid bioavailability and milk protein synthesis; and decreased gluconeogenesis and milk lactose in dairy cows.

Nonhormonal drugs for contraception in men: a systematic review.

UNLABELLED: Nonhormonal drugs for contraception in men may have advantages over hormonal methods. The nonhormonal methods can have more rapid onset and less interference with androgen-dependent functions. This systematic review summarizes the clinical studies evaluating nonhormonal drugs administered to men for contraception. Relevant clinical results were found for gossypol, which is derived from the cotton plant, and for extracts of Tripterygium, a plant used in Chinese traditional medicine. Randomized, controlled trials were available on the efficacy of gossypol and on the effect of gossypol on potassium levels. Gossypol had problems with low efficacy and toxicity. For Tripterygium, 2 observational studies described men who were treated for rheumatoid arthritis. Although sperm density was lower among those taking Tripterygium, later reports indicated some toxicity. Nonclinical research continues on isolates of Tripterygium. No clinical studies for contraception in men were found for nonhormonal vaccines or neem, which is also a plant used for medicinal purposes. Clinical trials studied injecting styrene maleic anhydride into the vas deferens, but no comparative data were provided. At this time, no safe and effective nonhormonal drug is available for contraception in men. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to state that the number of studies concerning the use of nonhormonal drugs for male contraception are very limited, point out that the two nonhormonal drugs used to a small degree have varying results and serious side effects, and recall that there are limited clinical studies on use of vas deferens injections and vaccines in humans.

Nutrient content of whole cottonseed.

The objective of this study was to determine if the nutrient and gossypol contents and in vitro digestibility of 3 types of genetically modified whole cottonseed differed from traditional whole cottonseed. Samples of seed from traditional (no genetic modifications) and genetically modified varieties of cotton grown in 1999 and 2000 were analyzed. Genetic modifications included the insertion of genes to protect cotton from insect pests (Bt), and damage from glyphosate herbicides (RR), and from both (Bt/RR). Year effects were significant for in vitro dry matter (DM) digestibility, gossypol, DM, crude protein (CP), fat, neutral detergent fiber (NDF), acid detergent fiber (ADF), and ash. Higher rainfall resulted in higher CP, fat, and ash and lower NDF and gossypol. There were no differences among seed types for ground or whole seed digestibility, DM, CP, fat, NDF, ADF, ash, lignin, net energy for lactation, amino acids, total fatty acids, or seed index. Overall, the nutrient content and digestibility of varieties of genetically modified seed were similar to that of varieties of traditional whole cottonseed.

A combined regimen of gossypol plus methyltestosterone and ethinylestradiol as a contraceptive induces germ cell apoptosis and expression of its related genes in rats.

Attempts to develop gossypol and steroidal hormones alone as a male contraceptive have been tested for many years; however, both caused undesirable side effects that have prevented their acceptance. In this study, we formulated a regimen of combined gossypol at a low dose of 12 mg/kg or a high dose of 50 mg/kg plus methyltestosterone 20 mg/kg and ethinylestradiol 100 g/kg daily (12 mg G+H and 50 mg G+H) administered for 6 weeks in adult rats. The possible roles of germ cell apoptosis and related genes expression were studied by techniques of TdT-mediated dUTP nick end-labeling (TUNEL), agarose gel electrophoresis of low-molecular-weight DNA, in situ hybridization and reverse transcription-polymerase chain reaction detection. Results showed that germ cell apoptosis and related genes expression were significantly induced after combined drug administration. The apoptosis index increased 3.86- and 9.65-fold in the 12-mg and 50-mg G+H-treated groups, respectively, as compared to the control group. DNA ladder formation on the agarose gel further validated the findings of TUNEL-stained apoptotic cells. The apoptosis-related genes fas mRNA expression levels increased 0.44- and 1.39-fold, bax mRNA 0.74- and 2.56-fold, caspase-3 mRNA 0.60- and 1.29-fold, and caspase-9 mRNA 2.50- and 4.08-fold, respectively, in the 12-mg and 50-mg G+H-treated groups vs. the control group. These results indicated that our drug regimen applied as a contraceptive could induce rat germ cell apoptosis. The apoptotic process involved fas system, bax and caspase family genes and the apoptotic extent and cell types were gossypol dose-dependent.

[Immunomodulating effect of the novel water-soluble gossypol derivative Mebavin in adjuvant arthritis]. / Immunomoduliruiushchee deistvie novogo vodorastvorimogo proizvodnogo gossipola mebavina pri ad''iuvantnom artrite.

Investigation of the effect of mebavin on the model of adjuvant arthritis showed that this drug administered in a dose of 100 mg/kg exhibits immunomodulant and anti-inflammatory activity without negative influence on the nonspecific response of the organism. Combined administration of mebavin with prednisolone provides for a more effective and nontoxic treatment of adjuvant arthritis.

Effects of gossypol from cottonseed meal and dietary vitamin E on the reproductive characteristics of superovulated beef heifers.

Superovulated Hereford-Angus crossbred heifers (average 397 kg BW) were used to test the effect of feeding cottonseed meal (gossypol) and vitamin E on embryo quality and ovarian characteristics. Twenty-four heifers were assigned randomly to four treatments with six heifers per treatment. Treatments were the following dietary supplements: 1) SBM (soybean meal + 30 IU vitamin E/kg of diet DM); 2) SBM+E (soybean meal + 4,000 IU vitamin E x animal(-1) x d(-1)); 3) CSM (cottonseed meal + 30 IU vitamin E/kg of diet DM); and 4) CSM+E (cottonseed meal + 4,000 IU vitamin E x animal(-1) x d(-1)). Supplements based on cottonseed meal provided 43.5 g of total gossypol/d (37% negative isomer (-) and 63% positive isomer (+)). Blood samples were collected at the start of the experiment and every 3 wk thereafter up to 12 wk. Plasma a-tocopherol (alpha-T) concentration was affected by treatments (P < 0.05). Heifers supplemented with cottonseed meal had greater (P < 0.05) alpha-T concentration in plasma than heifers supplemented with soybean meal at each concentration of vitamin E. Supplementation at 4,000 IU vitamin E x animal(-1) d(-1) increased (P < 0.05) the concentration of a-T in plasma. Weight gain, hemoglobin and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P < 0.05) in cottonseed meal-fed animals; however, EOF was lowered (P < 0.05) with vitamin E supplementation. Heifers fed CSM and CSM+E supplements had greater (P < 0.01) concentrations of (-)-, (+)-, and total-gossypol in plasma, corpora lutea (CL), liver, and endometrium than heifers fed SBM and SBM+E supplements. Tissue alpha-T concentration increased with increased dietary supplemental vitamin E, particularly in great amounts in the CL. Because there was no adverse effect of gossypol on superovulation response or embryo development despite concentrations of gossypol in endometrium that are toxic to embryos, it is likely that systems exist in the reproductive tract to limit gossypol toxicity.

Long-term effects of feeding gossypol and vitamin E to dairy calves.

Male Holstein calves were used to test the effect of feeding 400 mg of free gossypol/kg of diet and to determine whether vitamin E could counteract gossypol toxicity. Fifty-two calves were allotted to treatments as follows: 1) soybean meal-based starter; 2) cottonseed meal-based starter; 3) cottonseed meal-based starter + 2000 IU of vitamin E/d per calf, and 4) cottonseed meal-based starter + 4000 IU of vitamin E/d per calf. Vitamin E supplementation (treatments 3 and 4) improved weight gain and feed intake over calves on treatment 1. Gossypol concentrations in plasma were higher in calves on treatments 2, 3, and 4 than in calves on treatment 1; however, no differences were observed among animals receiving the three cottonseed meal diets. Hemoglobin and hematocrit were decreased in calves receiving treatment 2, and vitamin E supplementation counteracted this effect (treatments 3 and 4). Plasma alpha-tocopherol concentrations were not affected by gossypol intake and followed the vitamin E supplementation pattern During the experimental period, 10 calves died, six from treatment 2 and two each from treatments 3 and 4. Necropsy findings from 4 of 10 calves were suggestive of gossypol toxicity. Histopathological examination revealed centrilobular necrosis in the liver and atrophy and vacuolation of cardiocytes. Feeding cottonseed meal caused death of some calves with gossypol related toxicity signs, but did not decrease plasma alpha-tocopherol; however, vitamin E supplementation increased performance and may have conferred some protection against gossypol toxicity.

Effects on performance, tissue integrity, and metabolism of vitamin E supplementation for beef heifers fed a diet that contains gossypol.

We conducted an experiment for 112 d with yearling beef heifers to evaluate the effects of cottonseed meal (CSM) fed with various concentrations of vitamin E on hematological and tissue components. Heifers were assigned randomly to four treatments, with eight heifers per treatment. The treatments consisted of the following dietary supplements: 1) CON, based on soybean meal with 30 IU vitamin E/kg; 2) GOS, based on CSM with 30 IU vitamin E/kg; 3) G+2E, based on CSM with 2,000 IU vitamin E x animal(-1) x d(-1); and 4) G+4E, based on CSM with 4,000 IU vitamin E x animal(-1) x d(-1). Supplements based on CSM provided 4.5 g of free and 50.5 g of total gossypol x animal(-1) x d(-1). The total gossypol present in the supplements was 29.1% of the negative isomer (-) and 70.9% of the positive isomer (+). Blood samples were collected at the start of the experiment and every 2 wk thereafter up to 16 wk. There was a time x treatment interaction (P<.01) for plasma alpha-tocopherol ( alpha-T) concentration; however, feeding gossypol did not decrease plasma alpha-T. Weight gain, retinol palmitate, retinol, beta-carotene (beta-C), hemoglobin, and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P<.05) in gossypol-fed animals; however, vitamin E supplementation lowered EOF (P<.05). Heifers fed the supplements GOS, G+2E, and G+4E had greater (P<.01) plasma (-)-, (+)-, and total gossypol than heifers fed CON from Collection 2 to the end of the experiment. There was a treatment effect (P<.05) on vitamin E and gossypol concentrations in different tissues, with no effect (P>.05) for trace minerals (Cu, Zn, Fe, and Se). Vitamin E concentration in tissue increased with increased dietary supplementation of vitamin E. In heart and neck muscle, (-)-gossypol was greater (P<.05) than (+)-gossypol, but the reverse was true for liver. Gossypol decreased in vitro lipid peroxidation of liver homogenate in tissues. Gossypol deposition in tissue was liver > heart > muscle. In summary, gossypol from CSM did not decrease concentrations of antioxidant vitamins, including alpha-T, vitamin A, and beta-C, or have any detrimental effect on performance of beef heifers.

Reproductive effects of feeding gossypol and vitamin E to bulls.

An experiment was conducted to determine the effects of long-term feeding of cottonseed meal on the reproductive traits of Holstein bulls. Holstein bulls approximately 6 mo of age were placed on the following treatments: 1) soybean meal + corn (CON); 2) cottonseed meal + corn (GOS); and 3) cottonseed meal + 4,000 IU vitamin E x bull(-1) x d(-1) (G+4E). The GOS and G+4E diets were formulated to supply 14 mg of free gossypol x kg(-1) BW x d(-1). These bulls had been in a previous experiment that evaluated the effects of feeding the same type of diets, but from 2 wk to 6 mo. of age. Percentage of motility, percentage of normal and live sperm, and daily sperm production were less (P<.05) in the GOS than in the other two treatments. Percentages of primary abnormalities and abnormal midpieces were greater (P<.05) in the GOS group than in the other two groups. At 12 and 16 mo. of age, bulls were given two assessments for sex drive traits. Bulls that received gossypol exhibited less sexual activity (P<.05) at the first test than bulls in other treatments. Vitamin E supplementation in bulls that received gossypol improved the number of mounts in the first test and the time to first service in the second test. There was a trend of gossypol to decrease and vitamin E to improve libido score. The results of the GOS first libido test may indicate lack of sexual maturity, which agrees with sperm production data. At the time of first test (12 mo. of age), none of GOS, two of CON, and six of G+4E bulls had reached puberty on the basis of experimental protocol. Long-term feeding of gossypol to Holstein bulls negatively affected some reproductive traits; however, vitamin E supplementation countered these adverse effects and even improved these traits.

Gossypol-induced hypokalemia and role of exogenous potassium salt supplementation when used as an antispermatogenic agent in male langur monkey.

In our earlier study, we have observed that hypokalemia in langur monkeys, following gossypol acetic acid (GAA) treatment (5 mg dose level) when used as an antispermatogenic agent, and potassium salt supplementation partially maintained body potassium level of the animals. The aims of the present investigation was to confirm further occurrence of hypokalemia in the monkey (comparatively at two higher dose levels) and the role of potassium salt in preventing occurrence of gossypol-induced hypokalemia. Highly purified gossypol acetic acid alone at two dose levels (7.5 and 10 mg/animal/day; oral) and in combination with potassium chloride (0.50 and 0.75 mg/animal/ day; oral) was given for 180 days. Treatment with gossypol alone as well as with the supplementation of potassium salt resulted in severe oligospermia and azoospermia. Animals receiving gossypol alone showed significant potassium deficiency with signs of fatigue at both dose levels. Enhanced potassium loss through urine was found in potassium-deficient animals, whereas animals receiving gossypol acetic acid plus potassium salt showed normal serum potassium with a less significant increase in urine potassium level during treatment phases. Other parameters of the body remained within normal range except gradual and significant elevation in serum transaminases activity. The animals gradually returned to normalcy following 150 and 180 days of termination of the treatment.

PIP: An earlier study conducted by the authors indicated that body potassium levels were partially maintained in male langur monkeys treated with gossypol acetic acid (5 mg) and potassium salt supplementation. The present study sought to confirm the persistence of hypokalemia at two higher dosage levels (7.5 and 10 mg/animal/day) and assess the role of exogenous potassium salt (0.50 and 0.75 mg/animal/day) in preventing gossypol-induced hypokalemia. The two dosages of highly purified gossypol acetic acid were administered alone and in combination with potassium chloride for 180 days. All regimens produced severe oligospermia and azoospermia. However, monkeys who received gossypol alone showed significant potassium deficiency with signs of fatigue at both doses. On the other hand, animals receiving gossypol acetic acid and potassium salt supplementation showed normal serum potassium with a less significant increase in urine potassium level during treatment. Also noted was a gradual but significant elevation in the activity of serum transaminases. All parameters returned to normal 150-180 days after treatment termination. The hypokalemic effect documented in this study with gossypol alone may be due to renal leakage and gastrointestinal disturbances.

Desarrollo y evaluación de un panqué enriquecido con harina de algodón / Development and evaluation of an enriched cake with cottonsedd meal

En Venezuela, los problemas nutricionales, específicamente la desnutrición caloricoproteica, se ha acentuado en los últimos años. Una posible solución lo constituye el enriquecimiento de alimentos con fuentes de proteínas, como las que contiene el residuo o torta de la extracción del aceite de las semillas de algodón. En este trabajo se caracterizaron las harinas de algodón obtenidas industrialmente y se utilizó hasta en un 15 por ciento en un panqué enriquecido, susceptible a ser utilizado en la merienda escolar. Se seleccionó el panqué de vainilla con 45 por ciento de harina de algodón debido a que la aceptabilidad a nivel de laboratorio fue de 97 por ciento. Se probó en una escuela con 1.009 niños de distintas edades, la aceptabilidad fue de 97 por ciento. Se concluyó que este producto, que suministra 395 Kcal y 13 g de proteínapor cada 100 g, podría ser utilizado para mejorar el aporte calóricoproteico de la merienda escolar

Allelochemicals in plant foods and feedingstuffs: 1. Nutritional, biochemical and physiopathological aspects in animal production.

Several allelochemicals (anti-nutritional/anti-quality factors) contained in some plant foods and feedingstuffs are outlined. These include the trypsin and amylase inhibitors, hemagglutinins, gossypol, cyanogenic glycosides, tannins, oxalates, phytin, saponins, glucosinolates, estrogens, coumarins, alkaloids and aflatoxins. The nutritional, biochemical and physiopathological implications of their ingestion in a wide range of animals are reviewed. These include impaired growth, feed consumption, efficiency of feed utilization, alterations of normal enzyme activities, organ atrophy, necrotic changes, lesions and changes in normal hematological indices. The induction of increased dietary requirements for such nutrients as methionine, lysine, vitamins and divalent ions (eg Fe, Ca, Mg and Zn) by some of these factors is discussed. Ameliorative measures aimed at minimizing the concentrations and anti-nutritional effects of these factors are processing and including additives in the diet, or genetic manipulations. There is a need to prevent both functional and nutritional damage of food proteins and other nutrients arising from excessive heat treatment.

Effects of gossypol and cottonseed products on reproduction of mammals.

Gossypol is a toxic factor indigenous to the cotton plant genus Gossypium. Concentrations of free gossypol contained in feedstuffs such as whole cottonseed and cottonseed meals vary considerably. Nonruminant animals are particularly sensitive to the toxic effects of gossypol, whereas ruminants are somewhat more resistant. Signs of gossypol toxicosis in nonruminants, preruminants, and ruminants are similar and include labored breathing, dyspnea, decreased growth rate, and anorexia but are not pathognomonic. Postmortem findings include generalized edema and congestion of lungs and liver, fluid-filled thoracic and peritoneal cavities, and degeneration of heart fibers. The antifertility effect observed in many nonruminant species is overshadowed by toxic effects, particularly in females. Gossypol seems to disrupt estrous cycles, pregnancy, and early embryo development in females of all nonruminant species studied. Probable mechanisms include an endocrine effect on the ovary as well as a cytotoxic effect on the uterus or embryo. The female ruminant seems to be relatively insensitive to the antifertility effect of gossypol; however, in vitro data indicate some inhibition of embryonic development and ovarian steroidogenesis. The antifertility effect of gossypol has been studied most in males of nonruminant species. The effects of gossypol in the male are both dose- and time-dependent. At effective doses, gossypol causes males to be infertile because of sperm immotility and depressed sperm counts. Specific mitochondrial damage in the tails of spermatozoa seems to render them immotile, and extensive damage to germinal epithelium may be responsible for depressions in spermatogenesis. In ruminant males fed diets containing gossypol, ejaculated sperm appears normal under light microscopy. The integrity of the membrane of sperm cells may be damaged. Extensive damage to the germinal epithelium has been shown in both rams and bulls fed diets containing gossypol and is of major concern.

Effects of gossypol content of cottonseed cake on blood constituents in growing-fattening lambs.

The effect of gossypol content of cottonseed cake given as a source of CP in lamb (n = 8) rations was examined on the following blood parameters: plasma total protein, albumin, globulins, urea, glucose, hematocrit, hemoglobin, and mean corpuscular hemoglobin concentrations. The diets were isonitrogenous and isocaloric and contained 0, 15, and 30% cottonseed cake for 62 d. Blood samples were taken at the beginning, middle, and end of the experiment. Plasma total protein and globulins were higher at d 30 of the experimental period, but plasma albumin concentration, hematocrit, and hemoglobin were higher at the beginning of the experiment; plasma urea concentration was higher at d 60, and plasma glucose concentration was lower at d 30 of the experiment. The highest fraction in all treatments was albumin, followed by alpha 2-globulin and beta-globulin fractions, and there was no gamma 1-globulin fraction at d 30 and 60 of the experimental period. Liver examination showed significant differences in free gossypol content and accumulation, total N, and total protein percentage among the three treatments. Gossypol toxicity was not observed. The absence of gossypol toxicity in these animals has been attributed to detoxification of free gossypol by the formation of gossypol-protein complex in the rumen.

Effects of dietary cottonseed meal, with and without iron treatment, on laying hens.

1. The effects of feeding a screw-press expelled cottonseed meal (CSM) to laying hens at dietary concentrations of up to 300 g/kg, were studied over a 10 week period. 2. The overall performance of hens fed on a 75g CSM/kg diet was not significantly different from controls but a 300g CSM/kg diet, containing 255 mg free gossypol/kg and 87 mg cyclopropenoid fatty acids (CPFA)/kg and giving daily intakes per hen of 26.2 mg free gossypol and 9.0 mg CPFA, significantly reduced food intake (P less than 0.01) and egg production (P less than 0.01). The 150g CSM/kg diet (daily intakes of 14.6 mg free gossypol and 4.8 mg CPFA per hen) did not produce adverse effects initially but egg production was slightly depressed towards the end of the experimental period. 3. Treatment of the CSM with a solution of ferrous sulphate hepta-hydrate for inclusion in a 300g CSM/kg diet (100 mg/kg supplemental dietary iron) further reduced food intake (P less than 0.05) and egg production (P less than 0.05). 4. Storage of eggs at warm temperatures for up to 1 month did not lead to discolourations of any kind in the CSM diet groups, but resulted in yolk mottling, a condition reduced by treatment of the CSM with iron. 5. Storage of eggs at cold temperatures for 3 months resulted in brown yolk discolouration and the initial stages of pink albumen discolouration in the 300g CSM/kg diet group; the brown yolk discolouration was reduced by treatment of the CSM with iron.

Effects of K salt or a potassium blocker on gossypol-related hypokalemia.

Gossypol was found to be an effective male contraceptive. The most serious side effect of gossypol contraception was the presumed lowering of serum potassium levels. The purpose of this present randomized and controlled study was to evaluate the merit of ingesting K salt or a potassium blocker while using gossypol. Results indicated that supplementation of K salt does not cause a reversal of the effect of gossypol on serum potassium levels and the blocker triamterene does not prevent loss of serum potassium.