Effect of wet feeding on growth performance of broiler chickens in a hot climate

1. The Guinea Savanna in the tropics is characterised by high diurnal temperatures, often beyond the thermo-neutral zone of modern poultry, which imposes heat stress on them. 2. An experiment was conducted to determine the effect of partially (12 h wet mash in the day and 12 h dry mash in the night) or wholly (24 h) feeding wet mash on the growth performance of broiler chickens. 3. Three treatments: dry mash (control), wet mash (day) + dry mash (night) and wet mash (day + night) were tested. At 28 d of age, a total of 120 broiler chickens (Hybro, Netherlands) were randomly divided, using a completely randomised design, into 12 groups of 10 birds, each with mean live weight of approximately 800 g/bird. A maize-soybean based grower mash (200 g CP/kg and 12·5 MJ/kg ME) was fed. The wet mash was prepared daily by addition of 1·3 parts of water to 1 part of dry mash and fed from 28 to 56 d of age. The birds were housed in raised-floor pens. Feed and water were given ad libitum and light provided 24 h. Mean daily room temperature was 28-29°C in the morning and 35-41°C in the afternoon. 4. Mean feed intake of birds fed the wet mash (174 g/day) or wet + dry mash (166 g/day) was higher than that of birds fed the dry mash (152 g/day). Mean live weight gain of birds fed the wet mash (64 g/day) or wet + dry mash (64 g/day) was higher than that of birds fed the dry mash (58 g/day). There were no differences in gain/feed ratios (0·38-0·39) of any of the treatments, neither were there any differences between the feeding of wet mash partly or wholly for all variables. 5. It was concluded that wet feeding, particularly during day-time, had the potential to improve growth performance of broiler chickens in a hot climate.     

Effect of Antioxidants During Bovine In Vitro Fertilization Procedures on Spermatozoa and Embryo Development

Increased amounts of reactive oxygen species (ROS) during in vitro fertilization (IVF) may cause cytotoxic damage to gametes, whereas small amounts of ROS favour sperm capacitation. The aim of this study was to investigate the effect of antioxidants [50 μ m β-mercaptoethanol (β-ME) and 50 μ m cysteamine (Cyst)] or a pro-oxidant (5 m m buthionine sulfoximine) on the quality and penetrability of spermatozoa into bovine oocytes and on the subsequent embryo development and quality when added during IVF. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes, and mitochondrial function, was diminished (p < 0.05) after 4-h culture in the presence of antioxidants. Oocyte penetration rates were similar between treatments (p > 0.05), but antioxidants adversely affected the normal pronuclear formation rates (p < 0.05). The incidence of polyspermy was high for β-ME (p < 0.05). No differences were observed in cleavage rates between treatments (p > 0.05). However, the developmental rate to the blastocyst stage was adversely affected by Cyst treatment (p < 0.05). The quality of embryos that reached the blastocyst stage, evaluated by total, inner cell mass (ICM) and trophectoderm cell numbers and ICM/total cell ratio was unaffected (p > 0.05) by treatments. The results indicate that ROS play a role in the fertilizing capacity in bovine spermatozoa, as well as in the interaction between the spermatozoa and the oocytes. It can be concluded that supplementation with antioxidants during IVF procedures impairs sperm quality, normal pronuclear formation and embryo development to the blastocyst stage.     

Transporting bovine oocytes in a medium supplemented with different macromolecules and antioxidants: Effects on nuclear and cytoplasmic maturation and embryonic development in vitro

We investigated whether supplementing the medium used to transport bovine oocytes with different macromolecules [foetal calf serum (FCS) or bovine serum albumin (BSA)] or a mixture of antioxidants (cysteine, cysteamine and catalase) affects their nuclear and cytoplasmic maturation and thereby affects their subsequent embryonic development and cryotolerance. Oocytes were transported for 6 hr in a portable incubator and then subjected to standard in vitro maturation (IVM) for 18 hr. The oocytes in the control groups were cultured (standard IVM) for 24 hr in medium containing 10% FCS (Control FCS) or 10% FCS and the antioxidant mixture (Control FCS+Antiox). The intracellular concentrations of reactive oxygen species (ROS) at the end of IVM period were lower in the oocytes subjected to simulated transport in the presence of a macromolecular supplement or the antioxidant mixture than that of the control group (FCS: 0.62 and BSA: 0.66 vs. Control FCS: 1.00, p < .05; and Transp: 0.58 and Transp Antiox: 0.70 vs. Control FCS: 1.00, p < .05). After IVM, the mitochondrial membrane potentials of the transported oocytes were lower than those of the non‐transported oocytes (FCS: 0.41 and BSA: 0.57 vs. Control FCS: 1.00, p < .05; and Transp: 0.48 and Transp Antiox: 0.51 vs. Control FCS: 1.00 and Control Antiox: 0.84, p < .05). The blastocyst formation rates (36.9% average) and the re‐expansion rates of vitrified‐warmed blastocysts (53%, average) were unaffected (p > .05) by the treatments. In conclusion, supplementing the medium in which bovine oocytes are transported with antioxidants or different macromolecules did not affect their in vitro production of embryos or their cryotolerance.