Early-age thermal manipulation and supplemental antioxidants on physiological, biochemical and productive performance of broiler chickens in hot-tropical environments.

Heat stress has been ranked as a critical environmental issue confronting chicken farmers worldwide because of its detrimental effect on the growth, performance and health of the birds. This study evaluated the effects of early-age thermal manipulation (EATC) and supplemental antioxidants on the physiological responses of broilers in a hot tropical environment. A total of 300 day-old Ross broiler chicks were allocated to five thermal and dietary treatments, having 5 replicates of twelve birds each. The treatments were: chicks reared using the conventional method (CC), chicks exposed to early thermal manipulation with a temperature of 38 °C at day 5 with no antioxidant supplementation (TC), TC plus vitamin E at 250 mg/kg of feed (TV), TC plus selenium at 0.5 mg/kg of feed (TS) and the combination of TS and TV(TVS). The experiment was laid out in a Completely Randomized Design and data collected were analyzed using SAS (2008). The results showed that TVS broilers had significantly higher (P < 0.05) body weights at the finisher phase than the other treatment groups. The feed conversion ratio of TVS broilers was comparable to the TV group but lower (P < 0.05) than the other treatments. Reduced levels (P < 0.05) of heterophil, lymphocytes and hetrophil and lymphocyte ratio were recorded in the TVS compared to TV, TS and TC broilers. On day 42, the rectal temperature was significantly higher in CC than those in other treatment groups, which were comparable. TVS birds had higher (P < 0.05) weights of spleen, liver and lower abdominal fat than other treatments. The lowest concentration of plasma malondialdehyde and the highest activity of superoxide dismutase and glutathione peroxidase were recorded in TV and TVS birds. The study concluded that the growth performance and oxidative status in broilers were improved by the combination of EATC with supplemental Se and vitamin E (TVS).

Research Note: Effect of egg storage length on spread of hatch window, chick quality, and organ development in Transylvanian naked neck chickens.

Two hundred and twenty eggs from Transylvanian naked neck (TNN) chickens aged 30 wk were used to determine the effect of storage length on hatch window, chick quality, and organ development. Forty-four eggs (11 eggs in 4 replicates) were stored in cold room (16±1.5°C) in batches for 0, 3, 6, 9, and 12 d before setting in incubator. Data collected were subjected to one-way analysis of variance. Hatchability of set and fertile eggs declined (P < 0.001) progressively as duration of storage increased, however, storage for 6 and 9 d differed not from each other. For 50% hatch, there was a decrease of 30 min/d in hatching time by 3 d-stored eggs before fresh eggs, while eggs stored for 6, 9, and 12 d had delay of 70, 65, and 30 min/d, respectively. Hatching commenced earlier (P < 0.01) in eggs stored for 0 and 3 d than in prolonged storage of eggs for 6 to 12 d. Eggs stored for 12 d recorded shorter (P < 0.001) hatch window than those stored for 0 to 9d. Significantly (P < 0.01) more eggs hatched per hour during hatch window in fresh eggs (3.9%/h) than other storage durations (1.70-2.12 %/h). Fresh and 6 d eggs hatched into heavier (P < 0.05) chicks (37.2 and 37.5 g, respectively) than 12d (32.7g). Chicks from 9 and 12 d storage were shorter in length than those for 0 to 6 d. Toe (P < 0.01) and shank+toe (P < 0.001) were longer in 0 d chicks than others. Activity and appearance were poorer (P < 0.01) in 12 d chicks than other groups. The quality of eye was better (P < 0.05) in 0 to 6 d chicks than 12 d group, however, 9 d chicks were similar to 12 d. Larger membrane remnant were found in 6 to 12 d chicks (P < 0.001) than in 0 d chicks, though not different from 3 d group. Navel of chicks from eggs stored for 0, 3, and 6 d were more closed than in 9 d, though not different from 12 d. Yolk remnant was larger in chicks of 3, 9, and 12 d storage length than in fresh and 6 d storage length. Tona score was higher in 0 to 6 d chicks than in 9 and 12 d chicks. There was no (P > 0.05) effect of egg storage length on chick yield and relative weight of chick organs. It could be concluded that in order to ensure good hatchability and quality chicks, TNN eggs could be stored for 3 d, but not beyond 6 d without intervention such as prewarming of long-stored eggs.

Effect of storage duration on egg quality, embryo mortality and hatchability in FUNAAB-ɑ chickens.

Effect of extended storage on egg quality, embryo mortality and hatchability in FUNAAB-ɑ chickens was determined. Hatchable eggs (n = 288; weighing 53.2 ± 4.67 g) collected from a flock of FUNAAB-ɑ layer breeder hens aged 32 weeks were stored in egg tray with broad end up under 16 ± 1.5°C for either 0, 4, 8, 12, 16 or 20 d. Before incubation, eight eggs from each group were evaluated for internal and external quality traits. Remaining eggs were set in an incubator and transferred into hatcher on embryonic day 18. Data collected were subjected to one-way analysis of variance. Egg weight loss (EWL; p < .001), surface area (p < .001), yolk diameter (p < .001), inner and outer blastoderm diameters (p < .05) and dead in germ (DIG; p < .001) increased with storage duration while yolk height (p < .001), yolk index (p < .001), albumen weight (p < .05), albumen height (p < .05), albumen index (p < .01), Haugh's unit (HU; p < .05), fertility (p < .001), hatchability of set (HATCHS; p < .001) and fertile eggs (p < .05) decreased. Weight losses of 0, 1.2, 2.2, 3.4, 4.6 and 6.1% were recorded in egg stored for 0, 4, 8, 12, 16 and 20 days respectively. Eggs stored beyond 8 days exhibited higher DIG and lower HATCHS. Shell percentage in 4 days storage (11.4%) was lower (p < .05) than in 16 days storage (13.4%). Shell thickness was similar in eggs stored for 0 to 12 days, but 8 days storage (0.60 mm) had thinner (p < .01) shell than day 16 (0.71 mm) and day 20 (0.73 mm) storage. Internal quality unit (IQU) was higher (p < .05) in fresh eggs (180.4) than in 12 days (167.8) and 20 days (167.8) stored eggs. Extended storage of FUNAAB-ɑ eggs caused EWL, surface area shrinkage, lowered HU and IQU, loss of yolk and albumen quality, increased blastoderm diameters and DIG, and decreased egg fertility and HATCHS from day 8 forward. Storing FUNAAB-ɑ eggs beyond 8 days reduced quality parameters; therefore, other mitigating factors are recommended when storing beyond 8 days.

Comparative evaluation of haemagglutination potential of haemolymph from two species of giant African land snails (Archachatina marginata and Achatina achatina).

A comparative study was conducted to evaluate haemagglutination potential in the haemolymph of two species of giant African land snails (Archachatina marginata and Achatina achatina). Three liveweight groups of snails (<100 g, 101-150 g and >150 g) were used with 4 replicates per liveweight per species for haemagglutination assay (HA). The effect of aestivation on haemagglutination potential was also evaluated. Erythrocytes (2%) from cattle, sheep, goat and chicken were used for HA assay. Results showed that agglutinin-like substances that agglutinate erythrocytes of sheep, goat, cattle and chicken were present in the haemolymph of the two species of giant African land snails. Effect of species was found to be significant (P < 0.001) on haemagglutination titre. Haemolymph of A. marginata, had higher haemagglutination titre than that of A. achatina across the three liveweight groups used in this study. Snail liveweight had no significant effect (P > 0.05) on agglutinin content of the haemolymph in both species. Agglutination level depended on the source of erythrocyte used. Sheep erythrocyte recorded the highest haemagglutination titre, followed by goat, cattle, and chicken in that order. To our knowledge, this is the first evidence that Giant African land snails (GALS) haemolymph contain agglutinins as previously reported for Helix species. This evidence may be the basis for its survivability in the wild and thus establish the use of GALS for African herbal medicinal applications.