Effect of starvation on the content of free amino acids in plasma of different breeds of hen

Summary Leghorn, Cornish and White Rock hens were subjected to starvation. Free amino acids were determined in blood samples taken after 48, 72 and 96 h of starvation. A progressive decrease in concentration of the majority of amino acids was found. Changes in amino acid concentrations during starvation were dependent on the breed of hen.     

Investigating social discrimination of group members by laying hens

Social relationships in domestic fowl are commonly assumed to rely on social recognition and its pre-requisite, discrimination of group-mates. If this is true, then the unnatural physical and social environments in which commercial laying hens are typically housed, when compared with those in which their progenitor species evolved, may compromise social function with consequent implications for welfare. Our aims were to determine whether adult hens can discriminate between unique pairs of familiar conspecifics, and to establish the most appropriate method for assessing this social discrimination. We investigated group-mate discrimination using two learning tasks in which there was bi-directional exchange of visual, auditory and olfactory information. Learning occurred in a Y-maze task (p < 0.003; n = 7/8) but not in an operant key-pecking task (p = 0.001; n = 1/10). A further experiment with the operant-trained hens examined whether failure was specific to the group-mate social discrimination or to the response task. Learning also failed to occur in this familiar/unfamiliar social discrimination task (p = 0.001; n = 1/10). Our findings demonstrate unequivocally that adult laying hens kept in small groups, under environmental conditions more consistent with those in which sensory capacities evolved, can discriminate group members: however, appropriate methods to demonstrate discrimination are crucial.     

A comparison of two methods for assessing critical flicker fusion frequency in hens

This paper compared two general methods for assessing critical fusion frequency in hens (gallus gallus domesticus). The first method was a conditional discrimination procedure with the stimuli presented successively. The second was a two-alternative forced-choice procedure with the stimuli presented simultaneously. It was found that both methods of stimulus presentation gave comparable results suggesting that either method is useful when investigating psychophysics in animals. The results also show that hens’ critical fusion frequency is considerably higher than that of humans which may account for hens’ inability to recognise images presented on standard computer or television monitors.     

鸡输卵管蛋白分泌部前后段的神经支配差异

将ＣＢ－ＨＲＰ分别注入母鸡输卵管蛋白分泌部的前半段和后半段,以研究其神经分布的差异,结果表明,支配前半段与后半段的神经元分布位置和数目均有一定差异。后半段接受来自胸２至腰荐１３（Ｔ２－ＬＳ１３）脊神经节的感觉神经,Ｔ１－ＬＳ１３交感于神经节、内脏神经节和肾上腺神经节的交感神经,盆神经节的副交感神经以及肠神经节的神经。前半段的感觉和交感神经的来源与后半段的基本相同,但前半段的副交感神经主要来自迷走神     

Effect of “restricted ovulator” gene on uptake of yolk-precursor protein

Summary The bulk of the yolk proteins and lipoproteins constituting the yolks of mature oocytes in birds are synthesized by the liver and transported via the plasma to the oocytes where they are incorporated by micropinocytosis. Evidence is presented indicating that oocytes of hens possessing a mutation identified by Jones, Briles, and Schjeide as a restricted ovulator gene fail to incorporate normal amounts and proportions of low density lipoproteins, lipovitellin and possibly other proteins making up the bulk of the yolk material. Plasma albumin is taken into the yolks but the other proteins synthesized by the liver for deposition within the oocytes accumulate in the plasma, attaining very high levels. The possible nature of the lock preventing normal deposition of the excluded yolk proteins is discussed.     

三种益生菌对种鸡肠内环境及生产性能的影响

本文考察了蜡样芽胞杆菌、乳杆菌和丁酸芽胞杆菌三种益生菌对种鸡肠内菌群、粪便ｐＨ值、氨含量、硫化物含量、水份等肠内环境指标和生产性能指标的影响,结果表明三种益生菌都能够改善种鸡肠内环境,减少腐败菌和腐败物质的含量,其中蜡样芽胞杆菌和丁酸芽胞杆菌的混合制剂对种鸡生产性能亦有明显的提高作用。     

鸡垂体前叶提取物诱导鸡超数排卵

Chicken anterior pituitary extract(CAPE) and acetone dried chicken anterior pituitary (ACAPE) were injected intraperitoneally into normal laying hens (‘ovulation suppressed’ following pretreatment with daily subcutaneous injection of PMSG) to induce multiple ovulations. The dose of PMSG, the effect of CAPE and ACAPE and the time required for induction of ovulation following injection of ovulation inducing hormone were determined. The results revealed that (1) when 75 IU PMSG was administered daily, egg laying stopped in 33% of the treated hens within 6 days after the first injection. However, the percentage of hens showing the same effects changed significantly (over 95%) within 3 to 6 days when the amount of PMSG was increased to 100 IU; (2) the number of ovulated ova was 1 00±0 00, 2 33±0 26,2 20±0 20 respectively after receiving 100 mg, 200 mg and 300 mg; the number of ovulated ova was 2 00±0 00, 2 86±0 48, 3 00±1 50 respectively after receiving 10 mg, 15 mg and 20 mg ACAPE; (3) The time from injection to ovulation in almost all hens was about 7 5 h except one hen ovulated about 6 5 h after receiving ACAPE .     

Interactive effect of dietary levels of calcium and 25-hydroxy vitamin D3 on the performance,serum biochemical concentration and digestibility of laying hens from 61 to 70 weeks of age

ObjectiveThe present research was conducted to evaluate the interactive effect of dietary concentration of calcium (Ca) and 25-hydroxy vitamin D3 (25OHD3) on the performance, blood composition and digestibility of laying hens.MethodsA total of 540 Hy-line brown laying hens aged 61 to 70 weeks were randomly allotted in a 3×3 factorial arrangement, consisting of three levels of 25OHD3 (0, 25, and 50 μg/kg) and three levels of Ca (3.5%, 4.0%, and 4.5%). All diets had basal concentration of 3,000 IU/kg of vitamin D3 including the 2,800 kcal/kg of metabolic energy and 16% of crude protein.ResultsThe results showed that interactive effect (p<0.05) between Ca and 25OHD3 was such that dietary 25OHD3 linearly increased interleukin-6 at all levels of Ca inclusion. Interaction (p<0.05) occurred with the highest parathyroid hormone in laying hens that received dietary concentration of Ca (3.5%) with 25OHD3 (50 μg/kg), and Ca (4.0%) with 25OHD3 (50 μg/kg). Egg production and egg weight significantly (p<0.05) increased in the 4.5% Ca group compared to the 3.5% to 4.0% Ca groups. Egg shell thickness and tibia bone length also increased (p<0.05) in groups fed a high-Ca diet (4.0% to 4.5%). Phosphorus digestibility significantly (p<0.05) increased along with dietary Ca level. Among the tested 25OHD3 groups, higher (p<0.05) egg production and tibia thickness were present in hens fed 50 μg/kg of 25OHD3. Furthermore, Ca digestibility serum Ca and 25OHD3 were significantly increased in group offered 50 μg/kg of 25OHD3.ConclusionThe results gathered in this study indicate that dietary concentrations of 4.0% to 4.5% Ca and 50 μg/kg 25OHD3 improve the performance of hens from 61 to 70 weeks of age.     

Sunflower Meal as a Major Vegetable Protein Source in Layers' Ration

Abstract

An experiment was conducted with Starcross layers to evaluate the replacement value of sunflower meal (SFM) for cotton seed meal (CSM) and sesame meal (SM). The birds (aged 24 weeks) were given 4 isonitrogenous and isocaloric rations containing 0,5, 10 and 15% dehulled sunflower meal. The substitution of SFM for CSM and SM did not generally affect the egg production, feed consumption, feed conversion nor did it have any effect on the quality of eggs as measured by Haugh Units (HU) and yolk index. Egg shell thickness, however, improved by increasing dietary levels of SFM. The feed costs per hen were generally lower for the SFM group since SFM was cheaper than CSM and SM.     

Transfer of stimulus control from a TFT to CRT screen

The use of television and computer screens for presenting stimuli to animals is increasing as it is non-invasive and can provide precise control over stimuli. Past studies have used cathode ray tube (CRT) screens; however, there is some evidence that these give different results to non-flickering thin film transistor (TFT) screens. Hens’ critical flicker fusion frequency ranges between 80 and 90 Hz - above standard CRT screens. Thus, stimuli presented on CRT screens may appear distorted to hens. This study aimed to investigate whether changing the flicker rate of CRT screens altered hens’ discrimination. Hens were trained (in a conditional discrimination) to discriminate between two stimuli on a TFT (flickerless) screen, and tested with the stimuli on a CRT screen at four flicker rates (60, 75, 85, and 100 Hz). The hens’ accuracy generally decreased as the refresh rate of the CRT screen decreased. These results imply that the change in flicker rate changed the appearance of the stimuli enough to affect the hens’ discrimination and stimulus control is disrupted when the stimuli appear to flicker.