Dietary supplementation of Eucalyptus leaves enhances eggshell quality and immune response in two varieties of Japanese quails under tropical condition.

The effect of dietary supplementation of Eucalyptus leaves (EL) powder on productive performance and immune response in 2 varieties of Japanese quail was investigated. A total of 180 twelve-week-old laying Japanese quails from 2 color varieties (gray and white) were randomly assigned and distributed according to a completely randomized design in a 3 × 2 factorial arrangement (dietary treatment × variety) forming 6 subgroups (30 each). EL were mixed with the diet in 3 levels (0, 0.1, and 0.2%). Each hen was individually housed in a wire cage of laying batteries and kept in an open house under hot environmental temperature. Productive traits were determined for an experimental period of 6 wk. Egg quality, carcass traits, blood parameters, and immune response were also determined. The results indicated that the productive traits were not significantly affected by EL supplementation. Shell quality and broken eggs significantly improved in quails fed a diet containing EL compared with those in the control. The quails fed a diet supplemented with 0.1% EL exhibited significantly higher cellular mediated and humoral immune responses than those in the other treatment groups. Glutathione peroxidase activity tended to be significantly increased by the dietary administration of EL at the level of 0.2%. Concerning quail varieties, it could be noticed that the gray quails exhibited higher productive performance, shell quality, and cellular immunity than the white counterparts. It could be concluded that supplementing a diet with 0.1 EL as a natural feed additive greatly enhances eggshell quality and immunocompetence and reduces number of broken eggs of Japanese quails raised under high environmental temperature.

Influence of probiotic supplementation on immune response in broilers raised under hot climate.

1. The objective of the study was to evaluate the potential effects of dietary probiotic supplementation and stocking density and their interaction on growth performance, humoral and cellular immune responses of broiler chickens raised under hot climate conditions. 2. A total of 1800 1-d-old unsexed broiler chicks (Ross 308) were allocated in a completely randomised 3 × 2 factorial design, with three concentrations of dietary probiotic (0, 200 and 400 mg/kg) containing 4 × 109 cfu/g of Bacillus subtilis and two stocking densities (12 or 18 birds/m2) in a total of 6 treatment subgroups. 3. Dietary probiotic and stocking density had no significant effect on live body weight, feed consumption and feed conversion ratio. 4. Dietary probiotic supplementation had a positive effect on serum immunoglobulin M (IgM) and cell-mediated immunity when compared to the control at 6 weeks of age, whereas serum immunoglobulin A (IgA) and immunoglobulin Y (IgY) were improved, but not significantly so. Dietary probiotic and stocking density had no effect on relative weights of the bursa of Fabricius and spleen. 5. Dietary probiotic supplementation had a positive significant effect on serum IgM concentration and cell-mediated immunity without penalising growth performance in broilers raised under high ambient temperature.

Influence of pre-storage incubation on hatchability traits, thyroid hormones, antioxidative status and immunity of newly hatched chicks at two chicken breeder flock ages.

Egg storage longer than 7 days is associated with negative effects on hatchability traits. Pre-storage incubation has been a suggested method to reduce the negative effects of long-term storage times by enhancing the developmental stage of the embryo and probably reducing the embryonic stress. The objective of the present study was to investigate the effects of pre-storage incubation and storage time on hatchability characteristics, chick quality and serum thyroid hormones, antioxidative properties and immunoglobulin Y (IgY) concentrations of newly hatched chicks at two breeder flock ages. A total of 8000 fertile eggs were obtained from two different ages of chicken breeder hens (Egyptian local cross, Inshas). Half of the eggs were collected from young breeder hens (28 weeks old) and the other half from old breeder hens (50 weeks old). In each breeder flock age, eggs were distributed in a completely randomized experimental design in a 2×4 factorial arrangement, with two storage periods (4 or 14 days) and four pre-storage incubation durations (0, 4, 6 or 8 h at 37.5°C). At 28 and 50 weeks of age, pre-storage incubation and its interaction with storage period influenced significantly the apparent fertility, hatchability of set eggs and hatchability of fertile eggs and this improvement in hatchability is attributed to the reduction in embryonic mortality (early, intermediate and late). Pre-storage incubation for 6 or 8 h elevated significantly the grade A chicks and reduced the grade B chicks in comparison with non-heated controls. Interestingly, for eggs stored for 14 days, pre-storage incubation for 6 or 8 h enhanced serum triiodothyronine, thyroxine, glutathione peroxidase activity, total antioxidant capacity and IgY concentrations significantly and decreased serum malondialdehyde concentration significantly in the newly hatched chicks. It could be concluded that pre-storage incubation enhanced the hatching results, improved the antioxidative properties, reduced lipid peroxidation and elevated the humoral immunity in the newly hatched chicks. Hence, several benefits might be gained by pre-storage incubation when fertilized eggs will be stored for long periods.

The effect of 1-week feed restriction on performance, digestibility of nutrients and digestive system development in the growing rabbit.

A 3 to 4 week feed restriction of about 20% to 25% of the free intake is widely applied in rabbit breeding systems to reduce post-weaning digestive disorders. However, a short intensive feed restriction is described in few studies and can be beneficial for growing rabbits due to a longer re-alimentation period. The aim of this study was to evaluate the effect of ad libitum (AL) and two restriction levels of feeding (50 and 65 g/rabbit per day) applied for 1 week on performance, gastrointestinal morphology and physiological parameters during the restriction and during the re-alimentation period. Rabbits were divided into three experimental groups: AL rabbits were fed AL, R1 rabbits were restricted from 42 to 49 days of age and received 50 g daily (29% of AL) and R2 rabbits were restricted at the same age and were fed 65 g of feed daily (37% of AL). In the 1(st) week after weaning and in the weeks after restriction, all the groups were fed AL. During the restriction period, daily weight gain (DWG) in R1 significantly dropped to 11% (experiment 1) and 5% (experiment 2) compared with rabbits in the AL group, although they were fed 29% of AL, whereas in the R2 group it decreased to 20% (experiment 1) and 10% (experiment 2). In the week following feed restriction, DWG in the restricted groups increased (P<0.001) to 166% and 148% in R1 and to 128% and 145% in R2. Restricted rabbits in both the experiments reached up to 90% to 93% of the final live weight (70 days) of the AL group. Over the entire experimental period, feed restriction significantly decreased feed intake to 85% to 88% of the AL group; however, the feed conversion ratio was lower (P<0.05) only in experiment 1 (-6% in R1 and -4% in R2). Digestibilities of CP and fat were not significantly higher during the restriction period and during the 1(st) week of re-alimentation compared with the AL group. Significant interactions between feeding regime and age revealed the shortest large intestine in the AL group at 49 days of age and the longest at 70 days in the AL and R1 groups. Small intestinal villi were significantly higher and the crypts were significantly deeper in the restricted groups. It could be concluded that short intensive feed restriction increased digestible area in the small and large intestines, including the height of villi and depth of crypts, which might be involved in the compensatory growth and defence mechanism.

High ambient temperature influences eggshell quality and calbindin-D28k localization of eggshell gland and all intestinal segments of laying hens.

Eggshell quality deterioration associated with heat stress is a well-known phenomenon. The involvement of the 28-kDa calcium-binding protein (calbindin, CaBP-D28k) localization in this failure is not clearly understood. To test a possible direct effect of ambient temperature on calbindin-D28k localization, 40 White Leghorn laying hens were housed in individual cages and exposed to high ambient temperature (30-33°C) and thermoneutral temperature (20-22°C) which served as a control. Eggshell quality characteristics and immunohistochemical localization of all intestinal segments and eggshell gland calbindin-D28k were performed under both environmental conditions. As expected, egg weight, eggshell thickness, eggshell percentage, and eggshell density were negatively affected by high ambient temperature (P ≤ 0.01). Immunohistochemistry showed that calbindin was localized in the intestinal enterocyte cytoplasm and glandular cell cytoplasm under thermoneutral conditions. However, the calbindin intensity was prominently decreased in ileum, cecum, colon, and eggshell gland under heat stress conditions. Therefore, it could be concluded that calbindin-D28k localization in intestinal segments and eggshell gland is negatively affected by high ambient temperature which might be related to the deterioration of eggshell quality characteristics under heat stress conditions.

Vitamin E and organic selenium enhances the antioxidative status and quality of chicken semen under high ambient temperature.

1. The effects of supplemental dietary vitamin E and organic selenium (Se), and their combination, on improving semen quality characteristics and antioxidative status were investigated in cockerels exposed to high ambient temperature. 2. A total of 36 Egyptian local cross males, 40 weeks old, were housed individually in cages in an open-sided building (average daily temperature ranged from 33 to 36°C and relative humidity from 60 to 70%). Birds were divided randomly into 4 experimental treatments (n=9 each): (1) control (basal diet without any supplementation with vitamin E or Se); (2) vitamin E (basal diet +200 mg α-tocopherol acetate/kg diet); (3) Se (basal diet +0.3 mg organic Se/kg diet); and (4) vitamin E+Se (basal diet +200 mg α-tocopherol acetate/kg diet +0.3 mg organic Se/kg diet). 3. Under heat stress conditions, inclusion of vitamin E and/or organic Se in the diets enhanced the semen quality traits, including the spermatozoa count and motility, and reduced the percentage of dead spermatozoa. 4. A combination of 200 mg/kg vitamin E with 0.3 mg/kg organic Se reduced the thiobarbituric acid reactive substance concentration in seminal plasma samples to about 28% of the controls; and also enhanced the seminal plasma glutathione peroxidase activity by two-fold compared with controls. 5. It was concluded that dietary vitamin E in combination with organic Se has a synergistic effect in minimising lipid peroxidation and improving the antioxidative status in seminal plasma of the domestic fowl, which probably translated into enhanced spermatozoa count, motility and reduced percentage of dead spermatozoa under heat stress conditions.

The impact of incorporation of n-3 fatty acids into eggs on ovarian follicular development, immune response, antioxidative status and tibial bone characteristics in aged laying hens.

The objectives of this study were to investigate the effects of different dietary sources of unsaturated fatty acids (fish oil (FO) and/or linseed oil (LO)) on laying performance, egg yolk fatty acid composition, ovarian follicular development, antioxidative properties, immune response and tibial bone characteristics in aged laying hens. A total of 100 Hisex Brown hens at 56 weeks of age were housed individually in laying cages in an open-sided building under a 16 h light:8 h dark lighting schedule. Hens were randomly divided into four experimental treatments (n=25 each). Birds were fed ad libitum diets containing 2.5% vegetable oil (C, control), 2.5% FO, 2.5% LO and a mixture of 1.25% LO+1.25% FO (LO+FO) from 56 to 68 weeks of age. Egg production, egg quality characteristics and yolk lipid profile were analyzed. At 68 weeks of age, ovarian follicles were classified and tibial bone characteristics were determined. Serum thiobarbituric acid reactive substance (TBARS), glutathione peroxidase (GSH-Px) activity and total antioxidant capacity were measured. Incorporation of n-3 polyunsaturated fatty acids (n-3PUFA) into the egg yolks has been successful by using dietary FO and/or LO. There were no significant effects of treatments on hen-day egg production, feed intake, egg weight, egg shape index, albumen height, Haugh units and yolk height. However, dietary FO and/or LO supplementation had a significantly positive effect on eggshell percentage, eggshell thickness and yolk color. At 68 weeks of age, there was no significant difference among dietary treatments for tibial bone measurements. Also, no negative effects were detected in ovarian follicular development and weights of the ovary and oviduct, expressed in both absolute terms and relative to body weight. Dietary 2.5% LO, 2.5% FO and a mixture of 1.25% FO+1.25% LO enhanced GSH-Px activity, total antioxidant capacity and antibody titers significantly in comparison with control. It could be concluded that inclusion of mixed sources of n-3PUFA in diets at moderate levels (2.5%) increased the n-3PUFA content and decreased the n-6/n-3 ratio content in the yolk, improved the antioxidative status, reduced lipid peroxidation, enhanced the antibody response and did not have any negative influence on ovarian follicular development and tibial bone characteristics in aged laying hens.

Organic selenium enhances the antioxidative status and quality of cockerel semen under high ambient temperature.

1. The objective was to examine the effect of supplemental dietary organic selenium (Se) on improving semen quality and antioxidative status in male domestic fowls exposed to high ambient temperature. 2. Thirty-six Egyptian local cross males, 42 weeks old, were housed individually in cages in an open-sided building under 16 h L:8 h D and were provided with commercial feed and water ad libitum. In the house average daily temperature ranged from 33 to 36 degrees C and relative humidity from 60 to 70%. Birds were divided into 4 experimental treatments (n = 9) and were fed the basal diet supplemented with 0 (control), 01, 02 or 03 mg organic Se/kg in the form of a yeast source (Sel-Plex) for 8 weeks. 3. Under heat stress conditions, inclusion of organic Se in the cockerel diets enhanced the semen quality traits, including the sperm count and motility and reduced the percentage of dead sperms in a dose-dependent manner. 4. In seminal plasma, organic Se supplementation ameliorated some of the adverse effects of heat stress on lipid peroxidation and antioxidative properties. The inclusion of organic Se (03 mg/kg) in the cockerel diets doubled seminal plasma glutathione peroxidase (GSH-Px) activity, compared to controls and reduced lipid peroxidation. 5. In conclusion, supplemental dietary organic Se improved semen quality characteristics when cockerels were subjected to heat stress. It increased both sperm count and motility, reduced the percentage of dead sperm and enhanced the antioxidative status of seminal plasma.

Effects of catecholamines on ovary morphology, blood concentrations of estradiol-17beta, progesterone, zinc, triglycerides and rate of ovulation in domestic hens.

The present study is an attempt to shed more light on the role of epinephrine (EP) and norepinephrine (NE) in regulating ovarian follicular development, folliculogenesis and ovulation in laying hens. Sixty Egyptian local cross females (Mandarah), 50 weeks old, were individually housed and equally divided into three treatments: control (saline, 0.9% NaCl), EP (0.15 mg epinephrine/hen/day) and NE (0.75 mg norepinephrine/hen/day) (n=20). Animals were injected intramuscularly once a day for 15 successive days. At the end of the experimental period, 10 females from each treatment were randomly chosen, weighed and killed by decapitation. Ovaries and oviducts and ovarian follicles were examined. Plasma concentrations of estradiol-17beta, progesterone, zinc and triglyceride were determined. Results indicated that the ovaries of NE- and EP-treated hens were more developed than those of control hens being heavier and containing more yellow yolk-filled follicles. EP or NE significantly increased the ovulation rate and plasma concentrations of estradiol-17beta, progesterone, zinc and triglyceride compared with control treatment. It could be concluded that catecholamines may have a part in promoting ovarian follicular development and in stimulating ovulation in laying hens at the end of their reproductive lives.