Morphology and water and lipid contents of stifle menisci of growing swine.

Morphology and distribution of water and lipid were examined in menisci of growing swine. The broadness of menisci and the size of protruded tissue in the inner anterior portion of menisci varied among animals. Small tears of tissues were frequently observed. Both the thickness and tissue weight were greater in the lateral than in the medial meniscus. Water content and intensity of glycosaminoglycan staining with safranin-O were found to be greatest in the inner one-third of the meniscus, and greater in the middle than in the outer one-third of the meniscus. Lipid content was greater in the outer one-third than in the inner two-thirds of the meniscus.     

Effects of poor forage conditions on the behaviour of grazing ruminants

Summary This paper shows that the study of animal behaviour is a valuable aid to the improvement of the management of grazing livestock under extensive conditions. The food available to grazing animals in developing countries, and particularly in the dry season in the tropics, is often of very low quality and, in addition, is frequently available at low densities per unit area. Grazing ruminants attempt to adapt to these adverse conditions by increasing the time for which they graze each day and also by dispersing more widely. However, the time for which animals can graze may be limited by solar radiation and fly irritation in the day, and by the confining of the animals in pens at night. The adverse effects of the above limitations may be partially overcome when adapted local breeds are used. Dispersion of animals improves their ability to make use of extensive pasture and in order to encourage it, an understanding of the factors that affect it such as breed difference, social behaviour, adaptation and location of watering points and other unique environmental factors must be achieved. The paper concludes with recommendations of areas worth further research.

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Effecto De Malas Condiciones Del Forraje Sobre El Comportamiento De Rumiantes En Pastoreo

Resumen Este articulo demuestra la importancia de estudiar el compartamiento de animales en pastoreo, para mejorar el manejo extensivo. El forraje disponible por unidad de superficie en países en vías de desarrollo es escaso y de mala calidad, sobre todo en época seca. Los rumiantes tratan de adaptarse a estas condiciones adversas incrementando el tiempo de pastoreo y dispersándose. Sin embargo el tiempo de pastoreo puede estar limitado por la radiación solar y la irritación causada por moscas durante el dia o porque los animales son encerrados durante la noche. Estos efectos pueden contrarrestarse utilizando razas criollas y bebederos estratégicamente localizados. Se requiere entonces más profundidad en estudios etológicos para incrementar la productividad de animales en pastoreo extensivo.

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Effets De Mauvaises Conditions Fourrageres Sur Le Comportement De Ruminants Au Paturage

Résumé Cet article montre que l'étude du comportement animal est une aide appréciable pour l'amélioration de la conduite du bétail au pâturage en élevage extensif. La nourriture disponible pour les animaux au pâturage dans les pays en développement, particulièrement en saison sèche sous les tropiques, est souvent de très faible qualité et, de plus, fréquemment disponible en faible densité par unité de surface. Les ruminants essaient de s'adapter à ces mauvaises conditions en augmentant leur temps de pâturage chaque jour et aussi en se dispersant plus. Cependant, le temps de pâturage peut être limité par les rayons du soleil et l'irritation due aux mouches le jour, et par le confinement des animaux à l'enclos la nuit. Ces effets défavorables peuvent être partiellement surmontés par l'utilisation de races locales adaptées. La dispersion des animaux améliore leur possibilité d'utilisation des pâturages extensifs et pour favouriser cela, une compréhension des facteurs qui les affectent comme la différence de race, le comportement social, l'adaptation et la situation des points d'eau et d'autres facteurs du milieu doivent être considérés. L'auteur conclut en recommandant d'autres recherches valables pour ces régions.

     

Effect of cortisol on luteinizing hormone release during sexual behavior in the boar.

The effect of inhibiting the rise in cortisol concentrations that occurs at copulation upon luteinizing hormone release was studied in seven adult boars. Plasma samples were collected for assay of luteinizing hormone, testosterone and cortisol on a control day and before, during and after exposure to an estrous sow. The area under the curve was used to evaluate hormone production and treatment effects were evaluated by a paired Student's t-test. The 11 beta-hydroxylase inhibitor, metyrapone, was used to suppress glucocorticoid hormone production. Cortisol concentrations increased significantly (p less than 0.05) after breeding compared to values on the control day while treatment with metyrapone prior to breeding prevented the cortisol increase (p greater than 0.05). Although luteinizing hormone production increased significantly after copulation in both breeding experiments, metyrapone pretreatment resulted in a reduction of luteinizing hormone secretion (p less than 0.05). Testosterone production was also reduced in boars pretreated with metyrapone. The results suggest that the increased levels of cortisol occurring at copulation may enhance luteinizing hormone release in boars.     

Long form leptin receptor mRNA expression in the brain, pituitary, and other tissues in the pig

Much effort has focused recently on understanding the role of leptin, the obese gene product secreted by adipocytes, in regulating growth and reproduction in rodents, humans and domestic animals. We previously demonstrated that leptin inhibited feed intake and stimulated growth hormone (GH) and luteinizing hormone (LH) secretion in the pig. This study was conducted to determine the location of long form leptin receptor (Ob-Rl) mRNA in various tissues of the pig. The leptin receptor has several splice variants in the human and mouse, but Ob-Rl is the major form capable of signal transduction. The Ob-Rl is expressed primarily in the hypothalamus of the human and rodents, but has been located in other tissues as well. In the present study, a partial porcine Ob-Rl cDNA, cloned in our laboratory and specific to the intracellular domain, was used to evaluate the Ob-Rl mRNA expression by RT-PCR in the brain and other tissues in three 105 d-old prepuberal gilts and in a 50 d-old fetus. In 105 d-old gilts, Ob-Rl mRNA was expressed in the hypothalamus, cerebral cortex, amygdala, thalamus, cerebellum, area postrema and anterior pituitary. In addition, Ob-Rl mRNA was expressed in ovary, uterine body, liver, kidney, pancreas, adrenal gland, heart, spleen, lung, intestine, bone marrow, muscle and adipose tissue. However, expression was absent in the thyroid, thymus, superior vena cava, aorta, spinal cord, uterine horn and oviduct. In the 50 d-old fetus, Ob-Rl mRNA was expressed in brain, intestine, muscle, fat, heart, liver and umbilical cord. These results support the idea that leptin might play a role in regulating numerous physiological functions.     

Maternal immunization with vaccines containing recombinant NetB toxin partially protects progeny chickens from necrotic enteritis

Avian necrotic enteritis is a major economic and welfare issue throughout the global poultry industry and is caused by isolates of Clostridium perfringens that produce NetB toxin. Previously we have shown that birds directly vaccinated with inactivated C. perfringens type A culture supernatant (toxoid) combined with recombinant NetB (rNetB) protein were significantly protected from homologous and heterologous challenge. In the present study the protective effect of maternal immunization was examined. Broiler breeder hens were injected subcutaneously with genetically toxoided rNetB(S254L) alone, C. perfringens type A toxoid and toxoid combined with rNetB(S254L). Vaccination resulted in a strong serum immunoglobulin Y response to NetB in hens immunized with rNetB(S254L) formulations. Anti-NetB antibodies were transferred to the eggs and on into the hatched progeny. Subclinical necrotic enteritis was induced experimentally in the progeny and the occurrence of specific necrotic enteritis lesions evaluated. Birds derived from hens immunized with rNetB(S254L) combined with toxoid and challenged with a homologous strain (EHE-NE18) at either 14 or 21 days post-hatch had significantly lower levels of disease compared to birds from adjuvant only vaccinated hens. In addition, birds from hens immunized with rNetB(S254L) alone were significantly protected when challenged at 14 days post-hatch. These results demonstrate that maternal immunization with a NetB-enhanced toxoid vaccine is a promising method for the control of necrotic enteritis in young broiler chickens.     

Amino acid digestibilities in different samples of wheat shorts for growing pigs.

An experiment was carried out to investigate the variability in apparent ileal amino acid (AA) digestibilities in simulated samples of wheat shorts consisting of different proportions of wheat bran (WB), wheat shorts (WS), and wheat flour (WF), hereafter referred to as wheat fractions. The proportions of WS, WB, and WF and the NDF content (DM basis) of the wheat fractions were as follows: A, 70% WS, 30% WB, and 42.3% NDF; B, 85% WS, 15% WB, and 41.8% NDF; C, 100% WS and 41.3% NDF; D, 85% WS, 15% WF, and 35.2% NDF; and E, 70% WS, 30% WF, and 29.5% NDF. Six barrows, average initial BW of 37.2 kg, fitted with a simple T-cannula at the distal ileum, were fed one of six experimental diets according to a 6 x 6 Latin square design. Six diets were formulated to contain 17% CP (as-fed basis). Diets A, B, C, D, and E contained 17.53% soybean meal (SBM), which contributed 50% of the CP in these diets. The wheat fractions contributed the remaining 50% of the CP in these diets. Diet F contained 35.05% SBM, which was the sole source of dietary CP. Chromic oxide was used as the digestibility marker. During the first experimental period, the daily dietary allowance was provided at a rate of 5% (wt/wt) of the average BW. Thereafter, the daily dietary allowance was increased by 100 g at each successive period. Each experimental period comprised 12 d. Following a 7-d adaptation period, feces were collected for 48 h and ileal digesta for a total of 24 h. The apparent ileal digestibilities of AA in the wheat fractions were calculated using the difference method. The digestibilities were usually lowest in the wheat fractions containing WB and highest in those containing no WB. The average of the digestibilities of the indispensable AA was 63.5% for wheat fraction A, which contained 30% WB, and 71.9% for wheat fraction C, which did not contain WB. There were no differences (P > .05) in lysine digestibilities among the wheat fractions, which ranged from 54.7 to 64.1%. Of the indispensable AA, with the exception of arginine, lysine, and methionine, the apparent ileal digestibility values of AA were negatively correlated (P < .05) with the NDF content in the wheat fractions.     

Dietary protein concentration affects plasma arteriovenous difference of amino acids across the porcine mammary gland

The objective of this study was to determine whether the porcine mammary gland responds to increasing dietary CP concentration through changes in AA arteriovenous difference (a-v). Sixteen Landrace x Yorkshire lactating sows were provided ad libitum access to one of four isocaloric diets varying in CP concentration (7.8, 13.0, 18.2, and 23.5 %; as-fed basis). Litters were adjusted to 11 pigs within 48 h of birth. Sows were fitted with catheters in the carotid artery and main mammary vein on d 4. On d 10, 14, 18, and 22 of lactation, arterial and venous blood samples were obtained every 30 min over 6 h. Milk yield was estimated on d 11 and 21 using the D2O dilution technique. Final litter sizes on d 21 were 10.3, 11, 9.5, and 11 piglets for sows fed the 7.8, 13.0, 18.2, and 23.5% CP diets, respectively. Piglet ADG tended (P = 0.088) to increase with increasing dietary CP concentration and were 186, 221, 220, and 202 g for sows fed the 7.8, 13.0, 18.2, and 23.5% CP diet, respectively. Daily total milk yield on d 21 (kg milk/d) tended (P = 0.099) to increase, and average milk yield per nursed piglet (kg of milk-pig(-1)d(-1)) increased (P < 0.05) with increasing CP concentration and were, on a per-piglet basis, 0.95, 1.19, 1.14 and 1.13 kg of milk/d for the 7.8, 13.0, 18.2, and 23.5% CP diets, respectively. As dietary CP increased from 7.8 to 23.5%, isoleucine and leucine a-v increased linearly only (linear, P < 0.01); all other AA a-v increased, reached a maximum in sows fed 18.2% CP, and decreased thereafter in sows fed 23.5% CP (quadratic, from P = 0.10 to P < 0.05). Amino acid uptake by the entire udder and by each gland increased (linear, P < 0.05) with increasing dietary CP. Arteriovenous differences response to increasing day of lactation varied among AA, from no change for histidine, isoleucine, lysine, methionine, tryptophan, and valine, to a linear trend increase for arginine (P = 0.055), leucine (P = 0.064), phenylalanine (P = 0.101), and threonine (P = 0.057). In summary, for the majority of AA, a-v increased with increasing dietary CP concentration from 7.8 to 18.2%, but decreased when CP concentration exceeded 18.2%. In contrast, mammary AA uptake, piglet ADG and milk yield per pig increased linearly with increasing dietary CP, suggesting a coordinated regulation between AA delivery and transport to meet the demand for milk yield.     

花园高科维生素新项目成功投产

今秋十月,丹桂飘香.喜庆收获的日子里,2006年10月14日,“浙江花园生物高科股份有限公司胆固醇项目工程投产典礼”在浙江东阳花园集团隆重举行.来自农业部畜牧业司、中国饲料工业协会、浙江省畜牧兽医局,浙江省饲料工作办公窒、浙江省东阳市市委及全国名村等10多位领导,以及来自全国各地的特邀嘉宾等300余人参加了此次典礼.     

ORIGINAL ARTICLE: The approach to the mechanism of calcitonin gene‐related peptide‐inducing inhibition of food intake

The aim of this study was to investigate the anorectic mechanism of calcitonin gene‐related peptide (CGRP) in rats. Intraperitoneal injection of CGRP (50 μg/kg) resulted in decline (p < 0.05) in the food intake of rats at 0.5, 1, 2 and 4 h in comparison with saline control. Compared with saline‐treated group, the levels of hypothalamic 3′,5′‐cyclic adenosine monophosphate (cAMP) and plasma glucagon were increased (p < 0.05) in CGRP‐treated group, but insulin level was decreased (p < 0.05). No significant changes (p > 0.05) in the plasma leptin were observed between two treatment groups. Calcitonin gene‐related peptide injection down regulated (p < 0.05) both neuropeptide Y (NPY) and melanin‐concentrating hormone (MCH) genes at mRNA levels, but up regulated (p < 0.05) the expression of cholecystokinin (CCK) gene. The correlations analysis showed that food intake was negatively correlated (p < 0.05) with CCK mRNA, cAMP and glucagon levels. Moreover, there existed negative correlations (p < 0.05) between MCH mRNA and glucagon levels, and positive correlations (p < 0.05) between insulin and leptin levels. The results showed that cAMP acting as the second messenger may play a vital role in the anorectic effects of CGRP. Calcitonin gene‐related peptide could stimulate anorexigenic neuropeptides (i.e. CCK) and/or inhibit orexigenic neuropeptides (i.e. NPY and MCH) expression, and ultimately suppressed food intake that was functionally coupled to cAMP/PKA pathway activation.