Regulation of plasma oestrogen by dietary fats in the laying hen: Relationships with egg weight

1. Feeding a diet supplemented with maize oil was found to elevate plasma oestradiol concentration in laying hens.

2. In a larger‐scale experiment, isoenergetic and isonitrogenous diets containing 10, 20, 40 or 60 g/kg supplemental maize oil, tallow, coconut oil or fish oil were fed for 5 weeks.

3. Egg weights showed very different responses to the different fats. The responses could be described by quadratic functions that all gave optimum responses with supplemental dietary fat concentrations of about 40 g/kg. Egg weight increased the most with maize oil and was decreased with fish oil at the highest inclusion rate.

4. Measurements of egg components showed a relatively larger increase in albumen weights with maize oil than with other fats.

5. Across treatments, mean plasma oestradiol concentrations were very highly correlated (r = 0.96) with the changes in egg weights over the experimental period.

6. It is concluded that oestrogen is important in controlling egg weight and that the effect of dietary fats in influencing egg weight is mediated by an effect of the fats on oestrogen metabolism.     

饲用复合酶制剂在蛋鸡杂粕日粮中的应用效果研究

本试验旨在以棉籽粕、菜籽粕、花生粕为蛋白质来源的低成本饲料中添加饲用复合酶制剂 ,研究饲用复合酶制剂在蛋鸡杂粕日粮中的作用效果。1　材料与方法1 1　试验动物和试验饲粮　选择 1 0 0 0只 1 7周龄罗曼蛋鸡 ,随机分成 5组 ,每组 4个重复 ,每个重复 50只。 5组蛋鸡分别饲以 5种饲粮 :饲粮 1(玉米 -豆粕型 )、饲粮 2 (玉米 -杂粕型 )、饲粮 3(饲粮 2 0 1 %饲用复合酶制剂 )、饲粮 4(饲粮 2 0 2 %饲用复合酶制剂 )、饲粮 5(饲粮 2 0 3 5%饲用复合酶制剂 ) ,试验饲粮配方组成及营养水平见表 1。饲用复合酶制剂为珠海经济特区溢多利有…     

Increment of egg weight with hen age in various commercial avian species

1. The present study indicates that a common biological pattern exists for egg weight increase with hen age for the various commercial avian species, breeds and strains at their first laying cycle. Therefore, one common equation can be used for the estimation of egg weight increase.

2. The parameters estimated for this equation are based on (a) egg weights in terms of percentage of seasonal mean egg weight, and (b) age as percentage of maximum age of the hen. Therefore, if the season's mean egg weight is known for any species, breed or strain, the increase in egg weight can be easily predicted for the whole season, or for any particular hen age. For early prediction, egg weight expressed as a percentage of initial egg weight can be used, although such prediction will be somewhat less accurate.

3. The use of egg weight as a percentage of seasonal mean egg weight, and age as a percentage of maximum age, was found to overcome the differences between strains, breeds and even species, by applying the same denominators for egg weights and periods of lay.

4. At each point of hen age (mean egg weight), the egg weight grades can be easily estimated by employing the computerised Burr's (1967) equation. These values showed excellent fit with extensive field data, provided that only normal eggs and those originating from a single flock and from no more than two weeks of collection are counted.     

猪饲粮中添加脂肪的研究

猪饲粮中添加脂肪的积极作用已经得到了公认,脂肪的添加要视不同日龄的猪而定;同时,不同类型的脂肪具有不同的添加效果;此外,脂肪在添加过程中还受到了许多制约。因此,在猪饲粮中添加脂肪时,应综合考虑,从而使脂肪的正效应得到充分发挥。     

An appraisal of moulting on post-moult egg production and egg weight distribution in white layer hens; meta-analysis

1. The aim of this study was to establish how different moulting methods and body weight losses influenced post-moult performance and USDA egg weight distribution.

2. Data on 5 laying flocks (#34–38) of the North Carolina Layer Performance and Management Test were used in this meta-analysis.

3. The moulting methods were non-fasted moulted (NF), short feed restricted (SF), 13-d feed restricted (FR), non-anorexic moult programme (NA), non-anorexic moult programme with low sodium (NALS) as well as non-moulting programme as control treatment. The percentages of targeted body weight loss during the moulting period were 20, 24, 25 and 30% of body weight at the end of the first egg production cycle.

4. Post-moult egg production and egg mass were influenced by all moulting methods. Maximum increase in post-moult egg production rate and egg mass occurred with FR and NF programmes, respectively, at 30% of body weight loss, compared to non-moulted hens. Non-fasting methods reduced mortality rate more effectively than fasting methods.

5. Moulting resulted in increases in percentage of grade A and decreases in percentage of grade B eggs. Non-fasting methods increased percentage of grade A eggs more effectively than fasting methods. Percentage of cracked eggs decreased in moulted rather than non-moulted hens and the lowest rate was associated with the NA programme.

6. Post-moult egg weight was not significantly influenced by moulting methods. However, percentage of body weight reduction affected egg weight. The optimum increment in egg weight was achieved by 24% body weight reduction.

7. Overall, non-fasting methods resulted in similar egg production compared with fasting methods. Considering post-moult mortality and USDA egg weight distribution, non-fasting methods, especially NF and NA programmes, performed much better than fasting methods, indicating that non-fasting moulting methods, which are better for animal welfare, are effective alternatives to fasting methods.     

Partitioning of the response to protein between egg number and egg weight

1. Data from published trials with laying hens were examined to see whether the concentration of dietary protein needed to achieve maximum egg weight was greater than the amount needed to achieve maximum rate of lay. 2. It is concluded that both rate of lay and egg weight continue to show small responses up to the same level of protein (or limiting amino acid) input. 3. When predicting egg output using asymptotic models, a reasonable assumption is that small increments in dietary protein, close to the optimum, will evoke equal proportional responses in egg size and in rate of lay. 4. When protein supply is severely limiting, the major response is a reduction in rate of lay. Egg weight seldom falls below 0.90 of its maximum value, however inadequate the protein intake may be.     

The response of egg weight to the inclusion of different amounts of vegetable oil and linoleic acid in the diet of laying hens

1. Four diets containing different amounts of vegetable oil and linoleic acid were fed to White Leghorn hens throughout a full laying year.

2. Egg weight was poor with the low fat basal diet but increased in relation to the amounts of maize oil (4 and 30 g/kg) included in the diet.

3. With a diet containing 30 g olive oil/kg, egg weight was similar to that obtained with the diet containing the same amount of maize oil.

4. Rearing the birds on diets containing low or moderate amounts of linoleic acid did not affect the response to fatty acid content of the layer's diet.

5. It is concluded that the requirement of the laying hen for linoleic add is not higher than 9 g/kg but that egg weight does respond to higher dietary amounts of readily absorbable fatty acids.     

Astaxanthin Z-isomer-rich diets enhance egg yolk pigmentation in laying hens compared to that in all-E-isomer-rich diets

The effects of feeding diets containing astaxanthin with different Z-isomer ratios to laying hens on egg qualities, such as astaxanthin concentration in egg yolk and yolk color, were investigated. As the astaxanthin source, a natural microorganism Paracoccus carotinifaciens was used. Astaxanthin with different Z-isomer ratios was prepared by thermal treatment with different conditions and then added to the basal diet at a final astaxanthin concentration of 8 mg/kg. We found that, as the Z-isomer ratios of astaxanthin in the diet increased, the astaxanthin concentration in egg yolk and the yolk color fan score also increased significantly. Importantly, feeding a 50.6% Z-isomer ratio diet increased astaxanthin concentration in egg yolk by approximately fivefold and the color fan score by approximately 2 compared to that in hens fed an all-E-isomer-rich diet. Moreover, we showed that feeding Z-isomer-rich astaxanthin to laying hens increased plasma astaxanthin concentration by more than five times in comparison to that in hens fed an all-E-isomer-rich diet. These results indicate that Z-isomers of astaxanthin have higher bioavailability than that of the all-E-isomer and thus they exhibit greater egg yolk-accumulation efficiency.     

Incorporation of triticale in layer diets

1. Diets containing either maize or triticale were fed unsupplemented or supplemented with meat meal or groundnut oil to White Leghorn pullets for two periods of 11 weeks each.

2. The egg production of birds fed on the unsupplemented triticale diet was significantly higher than that of the birds fed on the unsupplemented maize diet, but was not significantly different from that of the birds fed on the maize plus meat meal diet.

3. Protein quality of the unsupplemented triticale diet as judged by efficiency of nitrogen retention was similar or inferior to that of the unsupplemented maize diet.

4. The higher protein content of triticale and the increased intake of these diets seemed to be responsible for the better performance observed.

5. Addition of groundnut oil to the triticale diet did not improve either egg weight or production.

6. It is concluded that the quantitative substitution for triticale of maize does not adversely affect egg production and egg weight.     

The estimation of egg weight from egg gradings

A method is described for the estimation of mean egg weight from data giving the proportions of eggs in different weight grades. Tables are presented in which mean egg weights have been calculated for a range of grading figures, using both the British Egg Marketing Board and the European Economic Community grading systems.     

The effect of supplementing layer diets with shark cartilage or chitosan on egg components and yolk lipids

1. An experiment was designed to evaluate the effects of the addition of shark cartilage (SC) or chitosan (CH) to layer diets on egg component weights, yolk lipids and hen plasma lipids. 2. Hy-Line laying hens (80) were used during a 56 d feeding trial. Treatments were: basal diet (BD), BD + 20 g/kg SC, BD + 30 g/kg SC, BD + 20 g/kg CH and BD + 30 g/kg CH. Eggs were analysed on d 14, 28, 42 and 56. 3. Egg weight and egg component weights were not affected by these treatments throughout the experimental period. 4. After 14d of experimental feeding, cholesterol levels were higher in eggs from birds given BD + 20 g/kg CH and BD + 30 g/kg CH than in those from birds given BD. 5. Furthermore, eggs from hens given BD + 20 g/kg SC or BD + 20 g/kg CH were higher in palmitic and stearic acids and lower in oleic acid than those from birds fed on BD. After 56 d feeding, however, palmitic and stearic acid contents in eggs from hens given any of the supplemented diets were lower than in those from hens given BD, and oleic acid in eggs from hens given BD + 20 g/kg SC, BD + 30 g/kg SC and BD + 30 g/kg CH was higher than in those from birds fed on BD. 6. Plasma cholesterol and triacylglycerol levels were not significantly affected by dietary treatment. 7. Shark cartilage or chitosan at up to 30 g/kg in layer diets did not affect egg component weights (yolk, white and shell) and total lipid contents. During the period from 42 to 56d of experimental feeding, diets containing up to 30 g/kg chitosan reduced egg yolk contents of cholesterol, palmitic and stearic acids and increased the content of oleic acid.     

肉鸡日粮中添加植酸酶的新认识

加入饲料中的植酸酶可提高氨基酸、蛋白质和能量的消化率 植酸盐,即植酸（肌醇六磷酸）的复合盐类物质,主要以植酸镁复合物的形式存在于所有植物性饲料原料中。植酸盐大约以10.0g/kg的浓度或以大约2.8g/kg的植酸磷浓度普遍存在于肉鸡日粮中。在家禽营养上,植酸盐很难被消化,所以植酸盐中的磷仅部分可被利用，并且植酸盐也有抗营养特性。植酸盐是一种多阴离子分子，     

Chokeberry polyphenols reduce prooxidative influence of oxidized fats in rat diets

The aim of the study was to estimate nutritional and physiological consequences of combined supplementation of rat casein diets with a strongly oxidized mixture of fats and extract of polyphenols from chokeberry. The experiment was conducted on 80 young Wistar rats divided into 8 groups. The animals were fed diets supplemented with 8% of fresh or oxidized fats and 0.4, 0.8 and 1.2% of polyphenol extract together. Addition of the oxidized fats caused significant reduction in animal growth without a decrease in nitrogen digestibility. On the other hand, the extract of polyphenols suppressed nitrogen utilization; animal growth was however similar to the control group. Analysis of the variance showed negative influence of the oxidized fats on cholesterol and triacyloglycerol concentration in the blood of the experimental animals. Increased activity of both aminotransferases in the blood of rats fed diets containing the oxidized fats indicated on liver malfunction. There was no effect of the experimental factors on the antioxidant status of the blood, but a dose-dependent reduced content of malonylodialdehyde in the blood of rats fed diets supplemented with the extract of polyphenols suggested that the extract had a preventive effect against prooxidative activity of the oxidized fats.     

提高蛋鸡产蛋率的技术措施

近年来,我国蛋鸡业生产发展很快,但就整体水平来看,其生产效率并不高。蛋鸡产蛋量的高低直接影响饲养者的经济效益,为了使鸡在产蛋阶段获得较高的产蛋量,延长产蛋高峰,除了搞好育雏、育成期的饲养管理外,还应注意以下几点。1选择高产蛋鸡随着养鸡业的发展,高产稳产的优良蛋鸡品种越来越多。在选择时,既要考虑到当地消费者的习惯与市场行情,又要选择产蛋多、耗料少、适应性强、料蛋比低的品种。2加强饲养管理2.1保持鸡舍整洁鸡粪是由饲料中未被消化吸收的部分以及体内代谢产物、消化道粘膜分泌物、肠道微生物及其分解产物等共同组成,在实际生…     

Feed value of supplemental fats used in feedlot cattle diets.

The inclusion of supplemental fats in growing-finishing diets for feedlot cattle also improves diet "condition." Quality factors that may influence the feeding value of fat include the source of fat; moisture, impurities, and unsaponifiables; free fatty acid concentration; degree of saturation or titer; and rancidity (peroxide value). The net energy value of fat declines linearly with an increasing level of supplementation because of constraints on postruminal fatty acid digestion. The authors recommend that receiving diets not contain more than 2% supplemental fat. Little evidence suggests that the feeding value of fat is different for Holsteins than for conventional beef breeds. Fat supplementation is not consistent in its effect on intramuscular fat distribution (marbling), longissimus (rib eye) area, and fat thickness, but can be expected to increase dressing percentage and kidney, pelvic, and heart fat percentage.     

提高蛋鸡全年产蛋量的五项关键措施

１培育好雏鸡，使胫长和体重双达标在饲养上充分利用蛋鸡在育雏期和育成前期骨骼生长发育快的特点，努力使雏鸡８周龄时胫长和体重双达标，并特别关注骨骼（胫长）的增长，为促进体型发育打下良好的基础。为了促进雏鸡体型发育，必须喂给高营养（高蛋白、高能量）的雏鸡饲料，只有在胫长达标后方能改换育成料。中型蛋鸡８周龄胫长为７８～８２mm，体重为６００～７００g。中型蛋鸡从４周龄开始每周称体重，检查体重增长情况，并及时调整饲养。２育成鸡的体重必须达标，并要求直线上升，育成后期应有一个较大的开产体重育成鸡中后期（１２～…     

Innovative layer genetics to handle global challenges in egg production

1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.

2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.

3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.

4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.

5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.     

The effect of variation in egg numbers,body weight and egg weight upon shell thickness

It is expected that when birds consume a diet with a fixed calcium content variation in the rate of egg production, in body weight or in egg weight will lead to variation in calcium consumption. This analysis investigated whether, in a particular experiment, this also led to variation in egg shell thickness. Data from 67 birds over ten consecutive 28‐d periods were considered. Within birds and within periods it was found that the relationships between shell thickness and these production characters varied at different dietary calcium levels and in some cases the partial regression coefficients calculated were different in sign from those expected. However, only comparatively small amounts of variation in shell thickness could be ascribed to yariation in egg numbers, body weight or egg weight and, after regression, significant (P<0.001) differences still existed in shell thickness between birds. In this investigation there was little tendency for the egg shells to become thinner as the birds aged and hence the correlation coefficients between shell thickness and each of the three production characters due to common seasonal or ageing effects were small. The correlation between the angular transformation of the percentage cracked egg shells produced by each bird and its'mean shell thickness was — 0.357.