The nutritional effect of <Emphasis Type="Italic">Moringa oleifera</Emphasis> fresh leaves as feed supplement on Rhode Island Red hen egg production and quality

This study aimed to evaluate the potential of Moringa oleifera fresh leaves (MOL) as feed supplement on the performance and egg quality of Rhode Island Red (RIR) hens under the tropical conditions of Yucatan, Mexico. Forty-eight RIR hens were allocated in 12 floor pen replicates each with four birds. Thereafter, the replicates were divided into three groups which were corresponded to ad libitum feed (control), ad libitum feed supplemented with MOL T1 (AL + MOL) and restricted feed amount (20% lower than control) with MOL T2 (RCD + MOL), respectively. T1 (AL + MOL) had higher egg laying rate (71.4% versus 66.6%), higher daily egg mass production (45.4 versus 41.9 g/day), lower feed intake (121.3 versus 127.5 g/day) and better feed conversion ratio (2.8 versus 3.2 g feed:g egg) versus control. T2 / (RCD + MOL) had lower values of body weight, egg laying rate, egg weight and egg mass, and recorded better feed conversion ratio than the control group. The control group recorded a higher percentage of pecked eggs versus T1 and T2 (6.5% versus 1.2% and 2.0 %). Similar intake of MOL (3.1 and 3.4 g DM/day) was recorded in T1 (AL + MOL) and T2 (RCD + MOL). Yolk color was improved significantly in T1 (AL + MOL) than both control and T2 (RCD + MOL), while T2 (RCD + MOL) had eggs with lower yolk and higher albumen percentages than the other two ad libitum groups. The results suggest that MOL could be used successfully as sustainable tropical feed resource for RIR hens.     

Egg production response of laying chickens to feather clipping,cool water and aspirin during hot weather conditions

An 8-week trial was conducted between March and May (hot-dry season) to determine effects of water temperature, feather clipping and aspirin on egg production of chickens. The treatments tested were hens given ordinary drinking water (control), cool water (100 g ice block per L) and aspirin (0.3 mg per L of ordinary water) and hens whose feathers were clipped (about two thirds of body feathers clipped). At 32 weeks of age, 120 Lohmann brown layer chickens of similar live weights were randomly divided into 12 groups of ten hens each and assigned to the treatments in triplicate using a completely randomized design. Feed and water were given ad libitum. Data included feed intake, water consumption, hen-day egg production and egg weight. Ambient house temperature, hen’s cloacal temperature and water temperature were monitored daily during the experimental period. Mean daily ambient temperature increased from 28.4 to 35.0 °C during the study period with consequent increase in cloacal temperatures (40.31 to 41.18 °C) of hens, ordinary drinking water and cool water. None of the treatments had any significant (P?>?0.05) effects on feed intake and water consumption of the birds. Hens given cool water produced more (P?P?P?>?0.05). It is concluded that the provision of cool water in a hot-dry climate had a beneficial effect on egg laying performance of chickens.     

Egg production and quality under three housing systems in the tropics

The aim of this study was to evaluate egg production and quality of Rhode Island Red (RIR) laying hens in an outdoor system in the subhumid tropic. Eighty RIR laying hens were measured in two periods and housed randomly under three treatments: outdoor (O), indoor (I) and in conventional cages (C). Egg weight (55.88, 53.76 and 57.16 g, for O, I and C, respectively), food intake/hen/day (138.94, 129.74 and 162.90 g, for O, I and C, respectively) and food efficiency (3.13, 3.22 and 3.96 for O, I and C, respectively) were significantly (P < 0.05) influenced by housing system; however, both egg production and final body weight were not different (P > 0.05). Yolk colour (10.76, 9.94 and 10.08 colour scale, for O, I and C, respectively), albumen weight (92.63, 92.28 and 90.08 g, for O, I and C, respectively) and yolk weight (15.19, 14.61, 15.48 g for O, I and C, respectively) were significantly (P < 0.05) influenced by housing system, but albumen height, Haugh units and egg shell weight remained similar (P > 0.05). Under the conditions of this study, outdoor egg production seems to be a sustainable system comparable to the commercial type based on wired cages.     

Effect of Dietary Carotenoid on Egg Yolk Color and Singlet Oxygen Quenching Activity of Laying Hens

The effects of dietary carotenoids on egg yolk were investigated in this study. Forty Rhode Island Red (RR) and 40 Silky Fowl (SF) hens that were 60 weeks old were used. Hens of each breed were randomly divided into four dietary groups. One group was fed a basal diet (crude protein 17%, metabolizable energy 2800 kcal/kg) only, whereas the other groups received a specific additive, namely, paprika extract, marigold petal extract, or Paracoccus cell powder, in addition to the same basal diet. The color and carotenoid content of egg yolk and singlet oxygen quenching activity were measured after 4 weeks. The total carotenoid content, zeaxanthin content, and singlet oxygen quenching activity in the yolk differed significantly between breeds and between diets (two-way ANOVA). The lutein content in egg yolk was affected by breed and diet, as well as by the interaction between these two factors. Regarding the Roche Yolk Color Fan values, only the effect of diet was significant. In terms of objective egg yolk color, there was a significant difference in lightness and yellowness between breeds. The total carotenoid content was higher in SF than in RR in all the groups. Likewise, the levels of zeaxanthin and lutein in the yolk were higher in SF than in RR (P<0.05). The results of the present study suggest that dietary carotenoids are effective feed additives for laying hens, especially SF, to improve the color and singlet oxygen quenching activity of egg yolk.     

Genotype X environment interaction in two breeds of chickens kept under two management systems in Southern Ethiopia

Rhode Island Red (RIR) and Fayoumi chickens were evaluated on-station in a college farm and on-farm in village farms, whereas local chickens were only tested under on-farm condition. Traits recorded are egg production and egg quality, body weight and feed efficiency at 4, 8 and 12 months of age. Significant age effect was found for most traits except for shell thickness, albumen height and egg length. Also, significant breed by management system interactions were found for all traits measured in both systems. Fayoumi chickens were higher in egg production in both management systems. Moreover, they were higher than RIR in feed efficiency. RIR were higher in most egg quality traits and had higher weight gain. Local chickens performed below the two exotic breeds in most of the traits, but had higher weight gain than Fayoumi. Chickens kept on-farm had poorer performance than those kept on-station in all traits except for yolk colour.     

Effects of dietary crude protein and electrolyte balance on production parameters and blood biochemicals of laying hens under tropical summer condition

The objective of this study was to determine the effects of different levels of crude protein (CP) and dietary electrolyte balance (DEB) on productive performance, egg quality, and blood biochemical parameters of laying hens reared during hot summer months. The average minimum and maximum room temperatures recorded from 32 to 42 weeks of age were 27.2 and 36.5 °C, respectively, with relative humidity ranging from 48 to 56 %. A total of 144 Lohmann LSL-Lite laying hens were assigned to each of four dietary treatments with six replicate cages of six birds. The treatments were as follows: CP 15.4 % + DEB 165 mEq/kg (group 1), CP 15.4 % + DEB 250 mEq/kg (group 2), CP 13.9 % + DEB 165 mEq/kg (group 3), and CP 13.9 % + DEB 250 mEq/kg (group 4). In groups 3 and 4, feed conversion ratio and blood uric acid were decreased (P?<?0.05); but the plasma triglyceride level was increased (P?<?0.05) compared to groups 1 and 2. Low-CP diet with DEB 250 (group 4) also induced significant increases of average egg production and eggshell thickness compared to group 1. Blood pH, Na⁺, and HCO₃ ^? values were also higher (P?<?0.05) in groups 2 and 4 than in the other groups. These results indicate that, under tropical conditions, using a DEB of 250 mEq/kg achieves a correction of the lay-induced metabolic acidosis and induces a positive effect on eggshell quality when the hens were fed low-protein diet.     

Digestibility,productive performance,and egg quality of laying hens as affected by dried cassava pulp replacement with corn and enzyme supplementation

Two experiments were conducted to investigate the potential use of dried cassava pulp (DCP) supplemented with enzymes as an alternative feed ingredient in laying hen diets. In experiment 1, 45 laying hens (Isa Brown) aged 45 weeks were placed in individual cages to measure nutrient digestibility for 10 days. Nine dietary treatments were control and DCP as a replacement for corn at 20, 25, 30, and 35% supplemented with mixed enzymes (cellulase, glucanase, and xylanase) at 0.10 and 0.15%. Results showed that the use of DCP at 20–35% added with mixed enzymes had no negative effects on dry matter digestibility, while organic matter digestibility and nitrogen retention decreased with increased DCP up to 30–35% in diets. Both enzyme levels (0.10 and 0.15%) showed similar results on nutrient digestibility and retention. In experiment 2, a total of 336 laying hens aged 32 weeks were randomly allocated to seven dietary treatments (control and DCP-substituted diets at 20, 25, and 30%) supplemented with mixed enzymes (0.10 and 0.15%). Diets incorporated with 20–30% of DCP and supplemented with mixed enzymes at both levels had no significant effects on egg production, egg weight, feed intake, egg mass, feed conversion ratio, protein efficiency ratio, or egg quality, except for egg yolk color being decreased with an increase of DCP in diets (P?<?0.05). In conclusion, it is suggested that DCP supplemented with enzymes can be used as an energy source in laying hen diets up to 30% without showing negative effects on nutrient digestibility, productive performance, or egg quality.     

Total loss and distribution of nitrogen and phosphorus in the outdoor run of organic laying hens

1. The objective of this study was to determine the level and variation of the total mass, and load of nitrogen (N) and phosphorus (P) excreted into the outdoor run of organic egg production systems.

2. Three egg production farms with an aviary system and an outdoor run were selected for this study. Four measurements, one per season, were executed on each farm.

3. Mean content of N and P of a manure dropping was 14·0?g N?kg^?1 and 3·12?g P?kg^?1, mean mass of a dropping was 6·36?g and mean dry matter content of a dropping was 238?g?kg^?1. Mean rate of excretion in the outdoor run was 2·99 droppings per hen per h. Mean percentage of hens outside during the time the outdoor run could be accessed was lowest on Farm 1 (1·7%), highest on Farm 2 (16·0%), and intermediate on Farm 3 (7·1%).

4. On all farms an exponential decrease of the number of hens and of the load of N and P with increasing distance from the hen house was found. Load of N exceeded the fertilisation standard (of 170?kg?ha^?1?y^?1) in the region at a 0 to 19?m distance from the hen house on Farm 1, 0 to 146?m on Farm 2 and 0 to 52?m on Farm 3.

5. It is concluded that the husbandry system should be redesigned to solve the problem of overloading, unwanted loss of N and P to the environment and loss of N and P from the organic production cycle.     

发酵饲料对蛋鸡生产性能、蛋品质、输卵管壁厚及卵泡分级的影响

试验旨在探究饲粮添加发酵饲料对蛋鸡生产性能、蛋品质、输卵管壁厚及卵泡分级的影响.取鸡舍环境条件趋于一致的580日龄海兰褐蛋鸡960只,随机分为4组,每组8个重复,每个重复30只鸡.各组饲粮分别添加0(A组)、2.0％(B组)、2.5％(C组)、3.0％(D组)发酵饲料.预试期1w,正式试验期6w.结果 显示,与对照组相...     

Effects of main cereal type and feed form on production performance,egg quality and egg sanitary indices of laying hens

ABSTRACT

1. The experiment was conducted to evaluate the effects of cereal types (maize or wheat) and feed forms (pelleted or mash feed) on production performance, egg quality and egg sanitary indices in laying hens.

2. Three hundred and sixty hens (Jinghong No. 1) at 18 weeks of age were randomly assigned to four treatments with six replicates of 15 hens per replicate according to a 2 × 2 factorial design with two cereal types (maize or wheat) and two feed forms (pelleted or mash feed).

3. Compared with the wheat-based diet, the maize-based diet improved (P < 0.05) average egg weight of laying hens. Yolk colour of hens fed with the maize-based diet was higher (P < 0.05) in comparison to those fed the wheat-based diet, while Haugh units were lower (P < 0.05) for the maize-based treatment. Egg mass and average daily feed intake of hens fed the pelleted diet were higher (P < 0.05) than of those fed the mash diet. However, the mash diet improved (P < 0.05) yolk colour compared with the pelleted diet. The percentage of dirty eggs for the wheat-based diet was higher (P < 0.05) than for the maize-based diet. The percentage of dirty eggs was higher (P < 0.05) in birds fed the pelleted diet compared with those fed the mash diet. There were interactions (P < 0.05) between cereal type and feed form, with regard to average egg weight and shell thickness.

4. In conclusion, dietary cereal type affected average egg weight, yolk colour and Haugh units in eggs, while feed form influenced egg mass, average daily feed intake and yolk colour.     

不同饲养方式对蛋鸡生产性能、鸡蛋品质及经济效益的影响

文章旨在评估不同饲养方式对蛋鸡生产性能、蛋品质和血清生化指标的影响.试验选择产蛋性能接近的22周龄海兰褐壳蛋鸡540只,随机分为3组,每组5个重复,每个重复36只.笼养组蛋鸡采用三层阶梯饲养(0.6?m2/只),网上平养组蛋鸡在金属网丝上饲养(1.5?m2/只),垫料平养组在平铺20?cm稻壳的水泥地板上平养(1.8?...     

饲料原料对蛋鸡生产性能和鸡蛋品质的影响

用三种来源不同的饲料饲喂商品蛋鸡,分别是全玉米豆粕饲料(A组)、河北购进的典型商品饲料(B组)和用杂粕配制的饲料(C组)。结果显示,A组产蛋率最高(76.8%),和C组(74.7%)差异显著(P<0.05)。平均蛋重三个组之间差异不显著。平均日耗料量A组(120.3g)低于B组(127.6g),高于C组(116g)。A组料蛋比和C组接近(2.43:1和2.42:1),均优于B组(2.63:1)。常规蛋品质三个组之间差异不显著,但是鸡蛋内容物中一些成分的含量存在差异。C组鸡蛋的水分含量稍高于A组和B组。三种鸡蛋中有毒有害物质含量均低于国家要求的标准,鸡蛋中没有检测出细菌。     

Pathogenicity and distribution of egg-drop syndrome-1976 virus (JPA-1) in inoculated laying hens

Rhode Island Red laying hens that lacked hemagglutination-inhibition antibody were inoculated orally with the JPA-1 strain of adenovirus isolated from a flock affected with egg-drop syndrome-1976 in Japan and observed for 80 days. Inoculated hens laid abnormal eggs, such as shell-less, soft-shelled, and cracked eggs and those with loss of pigmentation, from 8 days postinoculation (PI). Fifteen out of 16 hens laid abnormal eggs. Egg-production rte fell from 94% to 50% between 13 and 16 days PI. When the abnormal eggs were excluded, egg production was 17%; then it recoverd slowly, reaching 67% by the end of the experiment. The virus was recovered from various organs of inoculated hens from 3 to 7 days PI. Fluorescent antigens of the virus were observed in the epithelial cells and desquamated cells from the epithelium of the uterus and isthmus 10 and 14 days PI.     

强制换羽对蛋鸡生产性能和蛋品质的影响

旨在研究强制换羽对蛋鸡生产性能和蛋品质的影响。选取80周龄海兰褐蛋鸡4 500只,分为A、B、C组,每组1 500只,于试验组Ⅰ区饲养;选取60周龄海兰褐蛋鸡3 000只,分为D、E组,每组1 500只,于试验组Ⅱ区饲养;另选取60周龄海兰褐蛋鸡1 500只（F组）,于对照组Ⅲ区饲养。试验组Ⅰ区和试验组Ⅱ区位于同一栋鸡舍,对照组Ⅲ区位于另外一栋鸡舍。采取饲料、饮水、光照控制的方式对A~E组鸡群进行强制换羽处理;F组不进行强制换羽处理。试验包括7 d的预试期和56 d的正试期。在正试期内,测定各组鸡群的产蛋率、蛋品质指标、死亡率。结果表明：与换羽前相比,强制换羽后A、B、C组的平均产蛋率的提高幅度为27.1%,强制换羽后D、E组的平均产蛋率的提高幅度为16.1%,换羽后F组的平均产蛋率的降低幅度为5.5%;5个接受强制换羽处理的试验组（A~E组）与对照组（F组）相比,蛋重增加2.5%,蛋壳强度提高11.8%,蛋白高度提高8.8%,蛋形指数提高3.3%,蛋壳尖端的厚度提高14.8%;5个接受强制换羽处理的试验组（A~E组）的平均死亡率为2.5%,对照组（F组）的死亡率为1.5%。综上所述,强制换羽技术的应用可以明显提高海兰褐蛋鸡的产蛋率,并提升蛋品质。     

Growth rate and egg production of Creole and Rhode Island Red × Creole fowls

Summary In Guyana 3 experiments were conducted using 1,440 chicks and 640 pullets and the same number of hens in a randomised block design to determine the growth rate, egg production, and egg fertility and hatchability of1/2 Creole ×1/2 Rhode Island Red (CR) and3/4 Rhode Island Red ×1/4 Creole (CRR) fowls compared with the parental strains of Creole (C) and Rhode Island Red (R) fowls. The growth rate of CR and CRR was higher than C, but lower (P<0·05) than R. Total egg production per hen housed during the pullet year was 59.5, 106.8, 130.7 and 171.8 for C, CR, CRR and R respectively and they were all significantly (P<0·05) different. There were no significant (P>0·05) differences between the 4 strains for fertility and hatchability percentages of the eggs which averaged 87.8 and 88.9 respectively. The level of production was comparatively high and mortality low enough for the crossbreds to be recommended for smallholder poultry development, although the feed cost of production would be higher for CRR than for CR.

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Tasa De Crecimiento Y Produccion De Huevos De Gallinas Creole Y Rhode Island Rojas × Creole

Resumen Se condujeron tres experimentos en Guayana utilizando 1,440 pollitos, 640 pollonas e igual número de gallinas, en un diseño de bloques al azar, para determinar tasa de crecimiento, produccíon de huevos, fertilidad y tasa de nacimiento de 1/2 Creole × 1/2 Rhode Island Roja (CR) y 3/4 Rhode Island Roja × 1/4 Creole (CRR). Estos cruces fueron comparados con productos derivados de cepas paternas de Creole (C) y Rhode Island Roja (R). La tasa de crecimiento de CR y CRR fue más alta que aquella de C, pero más baja (P<0·05) que la de R. La producción total de huevos por pollona encasetada durante el año productivo fue 59·5, 106·8. 130·7 y 171·8 para C, CR, CRR y R respectivamente, siendo todas significativamente diferentes (P<0·05). No hubo diferencias significativas (P>0·05) entre las cuatro cepas, relacionadas con fertilidad y porcentaje de nacimientos de los huevos, los cuales promediaron 87·8 y 88·9, respectivamente. El nivel de producción fue comparativamente alto y la mortalidad suficientemente baja, para recomendar los cruces para el desarrollo avicola en fincas pequeñas, aunque el costo del alimento para producir, seria más alto para CRR que para CR.

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Rythme De Croissance Et Production D'oeufs Chez Les Poules Creoles Et Les Rhode Island Red × Creole

Résumé En Guyane, au cours de 3 expériences 1 440 poussins et 640 poulettes ainsi que le même nombre de poules ont été répartis en blocs équilibrés afin de déterminer le taux de croissance, la production, la fertilité et l'éclosabilité des oeufs chez des poules 1/2 Creole × 1/2 Rhode Island Red (CR) et chez des poules 3/4 Rhode Island Red × 1/4 Creole (CRR) en comparaison avec les souches parentales des poules Creole (C) et des Rhode Island Red (R).La croissance des CR et des CRR etait supérieure aux C mais inférieure (P<0,05) aux R. La production totale annuelle d'oeufs par poule était de 59,5, 106,8, 130,7, et 171,8 pour les C, CR, CRR et R, tous différents de manière significative (P<0,05). Il n'y avait pas de différences significatives (P<0,05) entre les 4 souches concernant les pourcentages de fertilité et le taux d'éclosion des oeufs qui étaient respectivement de 87,8 et 88,9 p. 100.Compte tenu du taux de production relativement élevé et d'une mortalité assez faible, il est possible de recommander ce croisement pour le développement de la production avicole pour les exploitations bien que le cout alimentaire de cette production soit plus élevé pour les CRR que pour les CR.

     

Feeding motivation on the incidence of floor eggs and extraneously calcified eggs laid by broiler breeder hens

1. Commercial broiler breeder hens lay many eggs on the floor rather than in nest boxes provided. A study was conducted to determine whether feeding feed-restricted broiler breeder hens during the sitting phase of nesting results in a higher incidence of floor eggs and/or retained eggs. 2. Sixty broiler breeder females (Ross 308) were randomly assigned to 6 deep litter pens containing 10 nest-boxes. At 35 weeks of age and for 9 weeks, feed was distributed to all pens at lights-on every second day (fed normally, FN). On alternate days (feeding delay, FD), feed was distributed when 2-3 hens/pen were sitting in a nest box. Behaviour was sampled at 41 weeks of age, for 26 d. Eggs and egg location data were collected daily, and eggs were scored for extra-cuticular calcium. 3. Of 81 instances in which the hen was sitting firmly in a nest box at the time of feeding, on 80 instances the hen left the nest-box to feed, and on one instance the hen laid her egg then exited to the feeder. Of these 80 instances, on 58 occasions the hen returned to a nest-box to lay her egg; on 12 the hen returned to the nest-box but laid no egg; on 7 the hen did not return to the nest box and laid no egg; and on three the hen laid her egg on the floor. 4. Mean floor egg percentage was 13·3 ± 3·2% on FN and 13·3 ± 4·7% on FD days; these did not differ significantly. 5. The mean extra-cuticular calcium score over all pens was 0·9 ± 0·06 on FN days and 1·2 ± 0·06 on FD days; these differed significantly. 6. In conclusion, feeding broiler breeder hens during nesting results in a conflict between feeding and nesting motivation and higher numbers of extraneously calcified eggs, but does not result in a significant increase in floor eggs even though nesting hens will leave the nest box for food.     

Effects of Scavenging on Diet Selection and Performance of Rhode Island Red and Fayoumi Breeds of Chicken Offered a Choice of Energy and Protein Feeds

An experiment was conducted to evaluate the effect of scavenging on diet selection and the comparative performance of Rhode Island Red and Fayoumi breeds of chicken. The breeds were compared under three feeding/management regimes: (1) a choice of ground noug cake and cracked maize, with confinement; (2) a choice of ground noug cake and cracked maize, but being allowed to scavenge for about 6 h; and (3) a commercial layer mash, with confinement. Scavenging did not change the pattern of diet selection. About 90% of the daily intake of both the confined and scavenging birds under choice feeding comprised maize. The efficiency of feed utilization and nutrient intake were also similar in these groups. The Fayoumi were more efficient in terms of feed conversion, although the egg production performance of the two breeds did not vary significantly. Scavenging hens had a significantly lower egg production than the birds under confinement offered a choice of feeds. Scavenging significantly increased the mortality in both breeds. In conclusion, scavenging affected the performance adversely and, despite the provision of a choice of feed providing a source of energy and protein, both the scavenging and confined birds on choice feeding failed to eat sufficient to meet their protein requirements.     

维生素E对免疫抑制产蛋鸡生产性能和蛋品质的调控效应

试验探讨维生素E对免疫抑制蛋鸡生产性能和蛋品质的调控效应,选取健康的尼克褐产蛋鸡270只,随机等分为5组,每组3个重复,每重复18只。第Ⅰ组为对照组,第Ⅱ~Ⅴ组为免疫抑制组,对第Ⅱ~Ⅴ组鸡在试验第5、6、7 d进行腿部肌肉注射80 mg/kgBW环磷酰胺(CTX),第Ⅰ组注射等量生理盐水。Ⅰ、Ⅱ组饲喂基础日粮(维生素E含量44.59 mg/kg),Ⅲ、Ⅳ、Ⅴ组在基础日粮中分别添加50、100、200 mg/kg维生素E。结果显示:①免疫抑制产蛋鸡的产蛋率、平均蛋重和平均日采食量显著降低(P<0.05),破蛋率显著升高(P<0.05)。基础日粮中添加50 mg/kg维生素E显著提高免疫抑制产蛋鸡的产蛋率、平均蛋重和平均日采食量(P<0.05),但仍低于对照组Ⅰ(P<0.05);显著降低料蛋比和破蛋率(P<0.05)。②免疫抑制产蛋鸡的蛋壳厚度、蛋壳强度和哈氏单位显著降低(P<0.05),蛋形指数和蛋黄颜色无显著改变(P>0.05);50 mg/kg维生素E添加量显著提高免疫抑制产蛋鸡的蛋壳厚度、蛋壳强度和哈氏单位(P<0.05),与对照组Ⅰ无显著差异(P>0.05)。因此,免疫抑制显著降低产蛋鸡的生产性能和蛋品质;基础日粮中添加维生素E对免疫抑制蛋鸡的生产性能和蛋品质具有明显的调控效应,且以50 mg/kg添加量效果较好。     

Effect of nutrient density on production performance, egg quality and humoral immune response of brown laying (Dahlem Red) hens in the tropics

A study was conducted to evaluate the effect of various concentrations of metabolizable energy (ME) with graded incremental levels of crude protein (CP) and essential amino acids (lysine and methionine) on production performance, egg quality and humoral immune response of Dahlem Red laying hens. Four experimental diets based on maize–soybean meal-deoiled rice bran were prepared. Diet 1 was fed as a control diet containing 2,600 kcal ME/kg, 15% CP, 0.75% Lys and 0.36% Met, and in the other three diets (D2, D3 and D4), concentrations of the above nutrients were increased by 2.5%, 5.0% and 7.5%, respectively. The levels of Ca (3.5%) and available P (0.32) were constant in all the diets. Each diet was offered ad libitum from 28 to 40 weeks of age to eight replicates containing six birds in each replicate. The egg production, egg weight and egg mass (in grams of egg per hen per day) were not affected by increasing the nutrient density up to 7.5% (2,795 kcal ME/kg diet) compared to the control group (2,600 ME/kg diet). However, feed consumption and feed efficiency (in grams of egg per gram of feed) were influenced by the variation in the nutrient density of diets. As the nutrient density increased by 5% (2,730 ME/kg diet), birds consumed significantly (P < 0.001) less feed. The birds in the 7.5% higher density group produced significantly (P < 0.05) higher egg mass per unit feed consumption compared to the control diet. Increasing nutrient density up to 7.5% had no effect on relative weight of albumen, yolk or shell. The Haugh unit, yolk colour and shell thickness were also not affected due to variation in the nutrient density. The humoral immune response measured at 34 and 40 weeks was progressively improved by increasing the nutrient density up to 5%. Increasing the nutrient density beyond 5% in the diet had no further influence on the humoral immune response. Based on the results of the present study, it can be concluded that Dahlem Red laying hens required 2,795 kcal/kg ME, 16% CP, 0.8% lysine and 0.4% methionine for eliciting optimum performance and immune response during 28 to 40 weeks of age.     

Effect of dietary defatted diatom biomass on egg production and quality of laying hens

Background

This study was to determine if feeding laying hens with defatted diatom microalgal biomass (DFA) from biofuel production affected their egg production and health status.

Methods

Five replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio (FCR), rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health.

Results

The 15% DFA diet decreased (P <?0.05) feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased (P <?0.05) egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent (P <?0.05) changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health.

Conclusions

Feeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.