Effect of feeding of calcium hydroxide-treated or vitamin E-supplemented cottonseed meal on plasma gossypol levels, blood parameters, and performance of Bikaneri lambs

To study the effect of feeding calcium hydroxide-treated or vitamin E-supplemented cottonseed meal (CSM) incorporated diets on plasma gossypol, blood parameters and animal performance, 24 male Bikaneri lambs of 6–7 months of age and of uniform body weight were divided into four groups of six animals each in a completely randomized design and respectively fed isonitrogenous and isocaloric concentrate mixtures containing 20 % soybean meal (CON) or 40 % raw CSM (RCSM), 40 % raw CSM supplemented with 500 IU of vitamin E per head per day (ERCSM), and 40 %, 1.5 % calcium hydroxide-treated CSM (CaCSM) along with ad libitum wheat straw throughout 510 days of experimental feeding. The lambs on all the diets grew linearly throughout the experimental period. The total weight gain, in turn the average daily gain (ADG), was not affected by dietary variations. The daily intake of dry matter, crude protein (CP), digestible crude protein (DCP) and total digestible nutrients (TDN) were found comparable among lambs of all the groups. Though total gossypol intake was similar in RCSM, ECSM and CaCSM groups, however, free gossypol intake was significantly higher (P?<?0.01) in RCSM, ECSM groups as compared to CaCSM group. Serum iron and blood hemoglobin levels were significantly (P?<?0.05) lower in RCSM group as compared to CaCSM and CON groups, and ALT activity was significantly (P?<?0.05) higher on RCSM group as compared to other groups. Plasma gossypol and osmotic fragility of erythrocytes were significantly (P?<?0.05) increased in RCSM group as compared to CaCSM and ERCSM groups. However, there was no significant difference in the concentration of other blood/serum biochemical constituents among the lambs on different groups. Based on the results, it may be concluded that feeding of 40 % CSM in the concentrate mixture of the diet in Bikaneri lambs did not have any major adverse effect in blood parameters and animal performance. Either calcium hydroxide treatment or vitamin E supplementation did not produce any major additional benefits.     

不同粉碎粒度对大豆分离蛋白(SPI)及棉粕分离蛋白(CPI)提取率的影响

采用传统的碱溶酸沉法提取了大豆粕及棉籽粕中大豆分离蛋白(SPI)及棉粕分离蛋白(CPI),并分别测定了棉籽粕,60目棉粕分离蛋白和80目棉粕分离蛋白中游离棉酚的含量,结果显示,60目及80目大豆粕中大豆分离蛋白的提取率分别为39.82%和44.95%(P<0.05),粗蛋白含量分别为81.07%和71.35%;60目及80目棉籽粕中棉粕分离蛋白的提取率分别为23.22%和35.39%(P<0.05),粗蛋白含量分别为76.03%和82.44%;棉籽粕、60目棉粕分离蛋白及80目棉粕分离蛋白中游离棉酚的含量分别为2182.54、522.79和503.87mg/kg(P<0.01)。综上所述,不同的粉碎粒度对大豆分离蛋白和棉粕分离蛋白的提取率有显著的影响,碱溶酸沉法显著降低了棉粕分离蛋白中游离棉酚的含量。     

无腺体棉籽饼作生长肥育猪蛋白饲料饲喂效果

用无腺体棉籽饼作为要生长肥育猪日粮中唯一蛋白质饲料进行了两次饲养试验。结果指出无腺体棉籽饼饲养效果明显优于有腺体棉籽饼并与豆饼相近。豆饼、无腺体棉籽饼和有腺体棉籽饼分别作日粮唯一蛋白质饲料,生长肥育猪日增重比为1.0:0.9～1.0:0.7～0.8。喂无腺体棉籽饼猪的肉中未检出游离棉酚,肝中也仅含5PPm。     

Effects of dietary cottonseed meal and iron-treated cottonseed meal in different laying hen genotypes

The effects of dietary screw-pressed cottonseed meal (CSM) and iron-treated CSM on laying performance and discolourations in eggs were examined in a range of hen genotypes. In experiment 1, six genotypes, obtained at point-of-lay from various sources, were fed on a non-CSM diet, a diet with 300 g CSM/kg, and a diet containing iron-treated CSM at 300 g/kg. In experiment 2, two of these genotypes were reared together from day-old and were fed from 10 to 18 weeks on a non-CSM diet or a diet containing iron-treated CSM at 250 g/kg. They were then fed on a non-CSM layer diet or a diet containing iron-treated CSM at 300 g/kg, in a 2 x 2 x 2 factorial design that also examined the effects of the rearing diet. 2. The effects on food intakes and egg production of including CSM and iron-treated CSM in layer diets depended on the genotype of the hens. The strongest interaction between breed and diet was on food intake, the breed Hubbard Golden Comet (HGC) being the least tolerant of CSM and iron-treated CSM. 3. Inclusion of iron-treated CSM in the rearer diet to supply approximately 70% of the dietary protein had no adverse effects on growth or age at first egg. Food intake and egg production between 18 and 26 weeks were affected by the iron-treated CSM layer diet, but there were no carry-over effects attributable to the rearing diets. 4. Genotype was not a factor in the development of the gossypol-related brown yolk discolouration in fresh or warm-stored eggs of hens fed on a CSM-based diet containing 197 mg free gossypol/kg and 52 mg cyclopropenoid fatty acids (CPFA)/kg (experiment 1). 5. In both experiments, the susceptibility of eggs to the CPFA-related cold storage effects depended on the genotype of the hen, eggs from hens of the HCG breed being more affected than those of ISA hens. 6. Treatment of CSM with crystalline ferrous sulphate heptahydrate, at a 4:1 weight ratio of iron to free gossypol, prevented brown yolk discolourations in all genotypes tested, as assessed by subjecting egg yolks to atmospheres of ammonia, and cold storage of eggs.     

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.     

Haematology, blood biochemistry and tissue histopathology of lambs maintained on diets containing an insect controlling protein (Cry1Ac) in Bt-cottonseed

This experiment assessed the effect of feeding genetically modified cottonseed (Bt) containing an insect controlling protein (Cry1Ac) on haematology, blood biochemistry and histopathology of lambs. Haemato-biochemicals were estimated at periodic intervals, and histopathology at termination of experiment. Thirty three weaner lambs were fed a composite feed mixture (CFM) ad libitum individually, in three groups for 123 days. The isonitrogenous CFM had roughage (Perl Millet Stover) and concentrate ratio of 350:650. Diet fed to control lambs contained groundnut oil meal as protein source while other two groups received diet containing either whole cottonseed (N-Bt) or Bt-cottonseed (Bt-CS). Daily feed intake and average daily gain were similar among lambs of three groups. Lambs fed N-Bt diet had higher (p < 0.05) serum protein and globulin compared to control and Bt diets, while albumin content was higher (p = 0.018) in Bt diet fed lambs. Serum urea and creatinin content, alkaline phosphatase (ALP) and serum glutamate pyruvic transaminase (SGPT) activities were not different among lamb groups, while urea and creatinin content and ALP activities increased linearly (p < 0.001) with increased feeding period. Blood haemoglobin (Hb), haematocrit (Hc), white blood cells (WBC), mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC) ranged from 11.1% to 11.2%, 31.8% to 32.8%, 7.0 to 8.3 (× 10(3) /μl), 19.1 to 22.5 fl and 33.2% to 35.5%, respectively, were similar among lamb groups. Erythrocyte sedimentation rate (ESR) (p = 0.008) and red blood cell counts (p = 0.006) were higher in Bt diet fed lambs. Control and N-Bt diet fed lambs had mild fatty infiltration in liver and/or micro-calculi in renal cortex, and such lesions were not seen in Bt diet fed lambs. Growth, haemato-biochemical and histopathology did not change by Bt-CS feeding in growing lamb. However, before recommending the use of Bt-CS in routine feed formulations prolonged feeding experiments of Bt-cotton seed require.     

高效降解游离棉酚并改善棉籽粕营养品质的菌株筛选

本试验旨在利用枯草芽孢杆菌和植物乳酸菌发酵棉籽粕,研究其对棉籽粕中游离棉酚降解率的影响,并对发酵前后棉籽粕的营养品质指标如活菌数、中性蛋白酶活性、酸溶蛋白质含量、pH、游离棉酚含量等进行比较。结果发现:可高效降解棉籽粕中游离棉酚的枯草芽孢杆菌菌株为BLCC1-0039,可有效改善发酵风味的植物乳酸菌菌株为BLCC2-0092。综合上述2株益生菌的优点,筛选出最优复配发酵方式为植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039按照1∶1比例接种,37℃需氧发酵24h再厌氧发酵。与空白对照组相比,最优复配发酵组各发酵阶段发酵棉籽粕的pH显著降低(P0.05),厌氧发酵72h时pH降至5.27;酸溶蛋白质含量显著提高(P0.05),厌氧发酵72h时酸溶蛋白质含量达到23.54%;游离棉酚含量显著降低(P0.05),需氧发酵24h时游离棉酚降解率达到52.12%,厌氧发酵72h时游离棉酚降解率达到61.58%。由此可知,植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039复配发酵可有效降低发酵棉籽粕中的游离棉酚含量并改善其营养品质。     

几种棉粕饲料的质量评定

试验旨在研究棉粕感官鉴定结果同其营养成分化学检验结果的相关性,为生产中感官检测提供理论依据。采集市面上不同产地及不同厂家的6种棉粕,测定其所含粗蛋白、游离棉酚、NDF、ADF、ADL的量。结果表明,6种棉粕所含游离棉酚量都在国标允许范围内,并且棉粕的色泽与游离棉酚含量有一定的相关性。试验数据表明,黄色棉粕较发红的棉粕游离棉酚含量高。棉壳含量是影响棉粕粗蛋白高低的主要因素,两者呈明显的负相关。棉壳和棉絮含量与纤维呈正相关,棉壳和棉絮含量过高则会影响到棉粕的品质。     

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol

The aim of this study was to evaluate the methane (CH₄) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH₄ emission. Twelve late-lactating Santa Inês sheep (44.8?±?7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH₄ emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH₄ emission was the sulfur hexafluoride (SF₆) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH₄ emission was evaluated considering the daily emission (g CH₄/day); DMI (g CH₄/kg DMI); and BW (g CH₄/kg BW). No statistical difference was found (P?>?0.05) between treatments for DMI and CH₄ parameters. In the regression analysis, no significant relation (P?>?0.05) between gossypol content and CH₄ emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.     

Effect of maternal cottonseed feed on the immune and antioxidant status of Santa Ines lambs

Cottonseed has been used as a nutritional alternative in animal production. However, consequences of this nutrient in the progeny is not well characterized. Thus, this work evaluated the effect on the immune and antioxidant status of the progeny of feeding Santa Ines ewe with or without cottonseed. Twenty-four Santa Ines ewes were distributed in two feeding regimes: cottonseed (CS) concentrate (n = 12) and soybean (SB) concentrate (n = 12). After birth, lambs remained with their mothers and blood samples were collected at 1^st, 3^rd, 7^th, 15^th, 30^th and 60^th day of life of 24 lambs born from mothers fed with (CS, n = 12) or without (SB, n = 12) cottonseed. Serum total protein, albumin, alpha beta globulin, gamma globulin, immunoglobulin G and M, activity of glutathione peroxidase (GPx), catalase (CAT), oxygen radical absorbance capacity (ORAC) and variables related to iron metabolism were affected only by sampling times (P < 0.05). The concentration of serum total protein, alpha beta globulin, gamma globulin and immunoglobulin G and M, GPx activity and ORAC values decreased as lamb age increased. Serum albumin concentration and CAT activity, in turn, increased as lamb age increased. In this work, maternal feeding with cottonseed did not affect the serum protein profile and antioxidant status of progeny during the lactation period, indicating no transfer of gossypol effects by milk secretions. Thus, the alternative in ruminants feeding with cottonseed can be used without maternal-descendant effects to immunity and oxidative stress in lambs.     

Effects of Cottonseed Cake-based Diets Supplemented with Blood Meal,alone or with lysine,on the Growth of Pigs

An experiment was carried out to establish the effect on the growth of pigs of including blood meal or lysine in diets containing gossypol from cottonseed cake. Forty Landrace x Large White pigs (20 of each sex) were randomly allocated to 5 treatments of 8 pigs each in a 2 x 2 factorial design with two levels of lysine or two levels of blood meal in the diets plus a control diet. The pigs were fed different diets and slaughtered at 75.0 +/- 2.0 kg live weight for carcase analysis. Supplementing the diets with blood meal resulted in higher live weight gains (p<0.001) and improved feed conversion ratios (p<0.001) than supplementing with lysine. Pigs fed the higher level of cottonseed cake showed a significant (p<0.001) depression in live weight gain and feed conversion ratio compared to those fed a low level of the cake. There was no significant difference (p>0.05) in intake in the pigs fed diets with cottonseed cake including blood meal or synthetic lysine. The kidney and liver weights of the pigs fed the diets with a higher level of cottonseed cake were significantly greater (p<0.001) than in those fed the lower level, but when the diets containing cottonseed cake were supplemented with blood meal or lysine at the same level there was no significant difference (p>0.05) in the weights of these organs. Lysine or other factors derived from blood meal appear to be more efficient than synthetic lysine in reducing the adverse effects of gossypol.     

膨化棉籽粕对蛋鸡生产性能、蛋品质及血清生化指标的影响

本试验旨在研究不同比例膨化棉籽粕替代豆粕对蛋鸡生产性能、蛋品质及血清生化指标的影响.选取40周龄海兰褐蛋鸡360羽,随机分成5组,每组4个重复,每个重复18羽.对照组饲喂玉米-豆粕型基础饲粮,试验1组用6％普通未膨化棉籽粕替代豆粕,试验2、3、4组分别用6％、8％、10％的膨化棉籽粕替代豆粕,试验期8周.结果表明:1)饲粮中不同比例膨化棉籽粕对蛋鸡生产性能影响不显著(P＞0.05),而试验1组产蛋率和平均蛋重显著低于对照组(P＜0.05),料蛋比显著高于对照组(P＜0.05).2)与对照组相比,各试验组蛋黄颜色均显著加深(P＜0.05),而试验1、4组蛋白高度显著降低(P＜0.05).饲粮添加棉籽粕对蛋壳强度和蛋壳厚度无显著影响(P＞0.05).3)试验1组总蛋白、钾含量均显著低于对照组(P＜0.05),谷丙转氨酶活性显著高于对照组和试验2组(P＜0.05),尿酸含量显著高于试验2组(P＜0.05);试验4组血清总钙含量显著低于对照组(P＜0.05).随着膨化棉籽粕添加量的增加,血清总蛋白、总钙和钾含量均逐步降低,谷丙转氨酶活性则逐步升高,呈现一定的剂量-效应关系.饲粮添加棉籽粕对血清白蛋白含量无显著影响(P＞0.05).由此可见,蛋鸡饲粮中添加8％膨化棉籽粕对蛋鸡生产性能、蛋品质及血清生化指标无明显影响.棉籽粕膨化处理能有效降低游离棉酚对蛋鸡生产性能和蛋品质等的影响,提高蛋鸡对棉籽粕的利用能力.     

Effect of expanded cottonseed meal on laying performance,egg quality,concentrations of free gossypol in tissue,serum and egg of laying hens

Three hundred and sixty Hy‐Line Brown hens, 40 week of age, were allocated to five treatments, each of which included four replicates of 18 hens. After an expanded process of cottonseed meal (CSM), free gossypol content in CSM was decreased from 1.24 to 0.40 g/kg. The dietary treatments were corn‐soybean meal based diets including 6% CSM and 6%, 8% and 10% expanded cottonseed meal (ECSM). Hens fed 8% ECSM had higher (P < 0.05) laying rate and average egg weight than those fed 6% CSM. The albumen height and Haugh unit in the control group, 6% and 8% ECSM groups were superior (P < 0.05) to other treatments. Hens fed 6% CSM resulted in severe (P < 0.05) egg yolk discoloration. Free gossypol (FG) concentrations in yolk and albumen and tissues of the 6% CSM group were greater (P < 0.05) than those in any ECSM treatments. Hens fed 6% CSM and 10% ECSM had the highest (P < 0.05) FG concentrations in the liver compared with those in the kidney and muscle, and higher (P < 0.05) FG residues in yolk than those in albumen. In conclusion, FG in CSM can be reduced by 68% through an expanded process and ECSM can be available in laying hens at up to 10% of the total diet and an appropriate replacement of soybean meal with ECSM may improve performance in laying hens.     

蒸汽爆破技术对棉籽粕中游离棉酚脱毒效果研究

本试验旨在研究蒸汽爆破技术对棉籽粕中游离棉酚的脱毒效果。采用市售棉籽粕,对其进行7种不同的蒸汽爆破处理,蒸汽压强均固定为2.0 MPa,以水料比为0时进行维压30 s的蒸汽爆破处理为对照,水料比为30%、50%时分别进行维压10、20、30 s的爆破处理,每处理重复3次,以游离棉酚含量、蛋白质溶解度为指标,筛选出较佳的处理测定氨基酸含量和营养物质猪仿生消化率数据。结果表明:固定蒸汽压强时,游离棉酚的脱毒率与蛋白质溶解度随着蒸汽维压时间延长而增加,随着水料比的增加先增大后减少。以游离棉酚的脱毒效果与蛋白质溶解度为指标,筛选出的适宜蒸汽爆破处理为蒸汽压强2.0 MPa,水料比30%,维压时间30 s。此时棉籽粕中游离棉酚含量达85.0 mg/kg,脱毒率达87.0%,蛋白质溶解度为42.3%。与对照组相比,蒸汽爆破可极显著降低棉籽粕中赖氨酸含量和精氨酸含量(P0.01),对体外干物质消化率和总能消化率无显著影响(P0.05),极显著降低体外粗蛋白质消化率和赖氨酸消化率(P0.01)。由此可见,蒸汽爆破处理可降低棉籽粕游离棉酚含量、蛋白质溶解度、赖氨酸含量、精氨酸含量、体外粗蛋白质消化率和赖氨酸消化率。筛选出的适宜蒸汽爆破处理为蒸汽压强2.0 MPa,水料比30%,维压时间30 s。     

固体联合发酵对棉粕发酵产物富肽蛋白产量及脱毒效果的影响

利用枯草芽孢菌（Bacillus subtilis NDX6）和植物乳杆菌（Lactobacillus plantarum BLLP）对棉粕、豆粕不同比例混合样品进行有氧和无氧联合发酵试验,并用纯棉粕进行联合发酵生长曲线研究,探讨固体联合发酵对棉粕发酵产物中富肽蛋白含量及脱毒效果的影响.结果表明,6个配方中纯棉粕发酵降解有毒物质游离棉酚含量最高约81％,游离氨基酸及小肽的含量提高约6.5倍（P＜0.05）,饲料pH由原来的6.20以上降低到5.12以下,有益菌活菌数提高约10倍;纯棉籽粕有氧发酵时间为38 h,无氧发酵时间60～66 h,游离氨基酸含量提高约7.54倍,游离棉酚降低约89％.用棉粕固体联合发酵可以脱毒,降解蛋白提高饲料吸收利用率.     

Effect of Nutrient Restriction and Realimentation on Growth and Metabolic Responses of Shorn Suffolk,Gulf Coast Native,and Crossbred Lambs

Growth and plasma hormone and metabolite levels were used to compare the effects of nutrient restriction and realimentation on six Suffolk (S), six Gulf Coast Native, (G) and seven S×G crossbred lambs. Shorn lambs were individually fed a 10% CP diet consisting of 20% cottonseed hulls, 74% ground corn, 1% soybean meal, 3% fish meal, 1.1% oyster shell flour, 0.5% urea, and 0.4% trace mineral salt and vitamin A, D, and E mixture. Lambs were fed at 110% of maintenance, 200% of maintenance, or had ad libitum access to feed during periods 1, 2, and 3, respectively. Each period was 28 d in length. Breed did not affect (P>0.25) weight change during nutrient restriction or realimentation. All lambs lost weight during the first period. The calculated NE_m of weight loss and 10% feed intake above maintenance suggests an 88% increase in maintenance energy requirement at 11.6 ± 0.9°C average temperature. Similar shorn G lambs maintained weight even though fed at 200% of maintenance, suggesting a 99% increase in NE_m. Plasma cortisol was lower (P<0.05) and thyroxine higher (P<0.05) in S than G or S×G lambs. Plasma cortisol levels were stable from d 14 through 42 declining to d 70 and increasing on d 84. Plasma thyroxine, urea N, and NEFA concentrations followed a similar pattern. There were differences between breed in plasma hormone levels but not plasma metabolite or weight change. Maintenance energy requirement of shorn lambs was increased.     

Effect of carbohydrate source and cottonseed meal level in the concentrate: IV. Feed intake, rumen fermentation and milk production in milking cows

Four early-lactation crossbred cows (82.5 % Holstein) were selected to investigate the effect of carbohydrate source and cottonseed meal level in the concentrate on rumen fermentation and milk production. Cows were randomly assigned to receive four dietary treatments according to a 2?×?2 factorial arrangement in a 4?×?4 Latin Square design. Factor A was carbohydrate source: cassava chip (CC) and CC + rice bran at a ratio 3:1 (CR3:1), and factor B was variation in the level of cottonseed meal (CM): low (LCM) and high (HCM) in isonitrogenous diets (180 g CP/kg DM). It was found that carbohydrate source did not affect feed intake, dry matter digestibility, rumen fermentation, microbial population, milk yield and composition, or economic return (P?>?0.05). However, cows fed with CC had a higher population of amylolytic bacteria than cows fed with CR3:1 (P?<?0.05). Cows fed with HCM had a higher total feed intake, milk yield and composition, and milk income when compared with cows fed on LCM although the concentrate and roughage intakes, dry matter digestibility, rumen fermentation, and microbial populations were similar between treatments (P?>?0.05). In addition, the carbohydrate source and cottonseed meal level interactions were not significant for any parameter. It could be concluded that cassava chip and high level of cottonseed meal could usefully be incorporated into concentrates for dairy cows without impacting on rumen fermentation or milk production.     

Heart failure caused by gossypol poisoning in two dogs

Two hound-type dogs from the same kennel were admitted in terminal stages of congestive heart failure. An investigation revealed the owner had been feeding the dogs cottonseed meal daily with their kibbled meal. Gossypol toxicosis from feeding this meal caused marked abnormalities in myocardial contractility. Although in severe congestive heart failure, one dog had only minimal dilatation of its heart, as revealed by thoracic radiography. Disseminated intravascular coagulopathy also was diagnosed in this dog. Gossypol is a cumulative toxin; the amount of free gossypol fed was approximately 5.4 to 5.7 mg/kg/day for an unknown duration.     

棉籽粕化学脱除棉酚的试验研究

本试验旨在探讨棉籽粕化学脱毒的最佳方法。试验1,通过研究不同水分、温度和作用时间对棉酚脱毒率的影响,确定棉籽粕的脱毒作用最佳水热条件。结果发现,在60~100℃、水分8%~16%和时间20 min~8 h条件范围内,随着温度、水分添加量、作用时间增加,棉籽粕脱毒率越高。试验2,比较10种常见单一化学脱毒剂的脱毒效果。研究发现,硫酸亚铁(Fe SO_4)、硫酸铜(Cu SO_4)和双氧水(H_2O_2)脱毒效果较佳,脱毒率均达到40%以上,然而,Fe SO_4脱毒棉籽粕颜色发黑并带有铁锈味,故Cu SO_4和H_2O_2为较优的单一棉酚脱毒剂。试验3,将Cu SO_4和H_2O_2制成混合脱毒剂,研究其最佳反应条件,并验证其脱毒效果。结果发现,80℃、16%脱毒剂添加量和烘1 h为最佳脱毒条件,且此混合脱毒剂的游离棉酚和结合棉酚的脱毒率均在84%以上;虽然脱毒后脱毒棉籽粕粗蛋白质含量稍微降低(P0.05),但粗蛋白质消化率显著提高(P0.05)。因此,水分、温度、作用时间都是影响棉籽粕化学脱毒的重要因素,在控制好这3个条件的情况下(80℃、16%脱毒剂添加量和密闭烘1 h时间),选用H_2O_2、Cu SO_4配制成一种混合脱毒剂,能有效脱除棉籽粕棉酚并且提高棉籽粕粗蛋白质消化率和仿生消化能,为棉籽粕脱毒加工提供良好的理论和技术支持。     

棉粕的营养组成及其在畜禽生产中的应用

棉粕是棉籽经过压榨、浸出等工艺得到的一种微红色或黄色的颗粒状物品,其粗蛋白的含量可达40%以上,仅次于豆粕,是优良的植物蛋白源之一。因此,常被人们当做饲料原料应用于养殖业中。但因棉粕中含有很多抗营养因子,如游离棉酚、单宁、植酸、环丙烯脂肪酸等,会对动物产生一定的毒害作用,使得棉粕在动物中的利用受到限制。对棉粕的营养组成及其在畜禽生产中的应用进行了综述,以期为棉粕在畜禽生产中的合理利用提供参考。