Ahmed A. Al-Haidary

Effects of dietary seaweed (Ulva lactuca) supplementation on the reproductive performance of buck and doe rabbits

The aim of this study was to investigate the effect of dietary supplementation of seaweed on the reproductive performance of rabbits. Two trials were performed during this study. In the first trial, semen quality was evaluated in 15 buck rabbits with mean body weight of 4.80±0.41 kg and six month of age. In the second trial, prolificacy was determined in 30 artificially inseminated does with a mean body weight of 4.84±0.50 kg and five to six months of age. Rabbits in each trial were randomly allocated to one of three dietary seaweed levels; commercial pelleted diet (C), pelleted diet supplemented with 1% seaweed (T1), and pelleted diet supplemented with 2% seaweed (T2). Dietary supplementation of seaweed significantly increased plasma testosterone concentration and improved various sperm motility parameters. Analysis of acrosomal membrane integrity using electron microscopy revealed no significant influences of dietary seaweed supplementation on quality grade (I–IV) of all tested samples. These results reflected in positive prolificacy response of does artificially inseminated with semen samples pooled from bucks fed on T2, and offered diet supplemented with 2% seaweed one week prior to their insemination and throughout the gestation period. Feeding diets supplemented with 2% seaweed to doe rabbits improved their kindling rate, litter size, and their offspring ratio. Seaweed supplementation to the diets of rabbits raised under summer conditions had improved their reproductive performance by improving the semen fertility characteristics of bucks and the prolificacy characteristics of does. Hematological and biochemical parameters investigated in this study did not reveal any pathological signs in both rabbits genders due to dietary seaweed supplementation.

Regional and circadian variations of sweating rate and body surface temperature in camels (Camelus dromedarius).

It was the aim of this study to investigate the regional variations in surface temperature and sweating rate and to visualize body thermal windows responsible for the dissipation of excess body heat in dromedary camels. This study was conducted on five dromedary camels with mean body weight of 450 ± 20.5 kg and 2 years of age. Sweating rate, skin and body surface temperature showed significant (P < 0.001) circadian variation together with the variation in ambient temperature. However, daily mean values of sweating rate, skin and body surface temperature measured on seven regions of the camel body did not significantly differ. The variation in body surface temperature compared to the variation in skin temperature was higher in the hump compared to the axillary and flank regions, indicating the significance of camels fur in protecting the skin from daily variation in ambient temperature. Infrared thermography revealed that flank and axillary regions had lower thermal gradients at higher ambient temperature (T(a) ) and higher thermal gradients at lower T(a) , which might indicate the working of flank and axillary regions as thermal windows dissipating heat during the night. Sweating rate showed moderate correlation to skin and body surface temperatures, which might indicate their working as potential thermal drivers of sweating in camels.

Dietary inclusion of chromium to improve growth performance and immune-competence of broilers under heat stress

This study was conducted to investigate the effects of dietary supplementation with chromium chloride, CrCl3.6H2O (2mg kg–1 basal diet) on the performance and immune response of broiler chickens under heat stress condition (25-43°C). A total of 80 one-day-old broiler chicks (Ross-308) were assigned to two treatment groups according to a completely randomized design. Each treatment consisted of four equal replicates, each contained ten chicks. Chicks were fed on basal diets supplemented with different concentrations of chromium (0 and 2 mg kg–1 CrCl3) from 1 to 35 days of age. Chromium supplementation as feed additives resulted in a slightly lower rectal temperature, and significantly (P<0.05) lower respiration rate for the broiler chickens received diet supplemented with chromium compared to the control (0 mg kg–1 CrCl3). Dietary chromium supplementation increased final body weight (BW) at the end of the production period (5 weeks). Average weight gain was significantly (P<0.05) higher in chickens fed on chromium supplemented diet. Feed intake was not influenced by dietary chromium supplementation, however, the efficiency of feed conversion was improved (P<0.05) in chromium supplemented chickens. Furthermore, dressing percentage was significantly (P<0.05) higher in Cr-treated chickens compared to control chickens. Chromium supplementation significantly (P<0.05) improved the immune response to Newcastle Disease Virus vaccine (NDV). The present results suggest that dietary chromium supplementation provides a good nutritional management approach to ameliorate heat stress induced depression in production performance and immune response of broiler chickens.

Daily Rhythms of Physiological Parameters in the Dromedary Camel Under Natural and Laboratory Conditions

Camels are well adapted to hot arid environments and can contribute significantly to the economy of developing countries in arid regions of the world. Full understanding of the physiology of camels requires understanding of the internal temporal order of the body, as reflected in daily or circadian rhythms. In the current study, we investigated the daily rhythmicity of 20 physiological variables in camels exposed to natural oscillations of ambient temperature in a desert environment and compared the daily temporal courses of the variables. We also studied the rhythm of core body temperature under experimental conditions with constant ambient temperature in the presence and absence of a light-dark cycle. The obtained results indicated that different physiological variables exhibit different degrees of daily rhythmicity and reach their daily peaks at different times of the day, starting with plasma cholesterol, which peaks 24min after midnight, and ending with plasma calcium, which peaks 3h before midnight. Furthermore, the rhythm of core body temperature persisted in the absence of environmental rhythmicity, thus confirming its endogenous nature. The observed delay in the acrophase of core body temperature rhythm under constant conditions suggests that the circadian period is longer than 24h. Further studies with more refined experimental manipulation of different variables are needed to fully elucidate the causal network of circadian rhythms in dromedary camels.