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 24 minutes after midnight, and ending with plasma calcium, which peaks 3 hours 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 24 hours. Further studies with more refined experimental manipulation of different variables are needed to fully elucidate the causal network of circadian rhythms in dromedary camels

Direct heat stress-induced effects on rumen fermentation characteristics and nutrients degradability in sheep pair-fed alfalfa hay

Aim of the study: To investigate the direct effect of heat stress on rumen fermentation characteristics and nutrients degradability of pair-fed rams to subsequently eliminate the confounding effects of dissimilar feed intake induced by heat stress exposure.Area of study: Saudi Arabia.Material and methods: Five rumen-cannulated desert rams (45 ± 1.63 kg body weight; 2–3 years of age) were placed individually in controlled climatic-chambers to be exposed to two successive periods. The 1st period was a control thermoneutral period (TN; 23.64 ± 0.14 °C; extended for 21 days) followed by a 2nd period of heat stress (HS; 44.26 ± 1.70 °C, for another 21 days). Each period was consisted of a temperature acclimation phase (7 days) and a data collection phase (14 days). Alfalfa hay was offered twice daily during both periods in a pair-fed manner (800 g DM per head and day).Main results: Exposing pair-fed desert rams to elevated ambient temperature had (p<0.05) elevated their respiration rate and skin temperature, without noticeable (p>0.05) changes in their rectal temperature. Most of the rumen fermentation characteristics and nutrients degradability were not affected by HS (p>0.05). However, exposure to HS increased (p<0.05) pre-feeding rumen total volatile fatty acids concentrations, pre-feeding molar proportion of acetate, and post-feeding rumen osmolality.Research highlights: HS had no direct effect on post-feeding rumen fermentation characteristics and nutrients degradability in desert sheep. This implies that strategic approaches to mitigate the adverse effects of HS have to be directed towards promoting feed intake and nutrients utilization under such conditions

Physiological responses of naimey sheep to heat stress challenge under semi-arid environments

Eight Naimey sheep were used in this study to determine the effect of heat stress on body temperature, heart rate and some blood constituents. The results show that exposure to heat stress challenge resulted in a significant increase in RT, RR, and skin temperature sites. Heart rate rhythm exhibit a circadian rhythm and exposure to heat stress reduce the heart rate mainly during the hottest part of the day. The effect of heat stress was also observed on total serum thyroxin and triiodothyronine.Corresponding Author: Dr. Ahmed A. Al-Haidary Animal Production Department, College of Agriculture, King Saud University, P.O. Box 52251, Riyadh–11563, Saudi Arabia Email: [email protected]

Effects of Different Levels of Yucca Supplementation on Growth Rates, Metabolic Profiles, Fecal Odor Emissions, and Carcass Traits of Growing Lambs

Sixty male Awassi lambs were used to investigate the effects of dietary Yucca schidgera extract (YS) on the production, fecal and urinary odor emissions, and carcass traits of growing lambs fed complete pellets. Lambs were fed either a complete pelleted diet without yucca (control) or supplemented with 300 or 600 mg YS/kg dry matter (DM) during the 84-day experiment. The weights and feed consumption of the lambs were measured weekly. Blood samples were taken on days 1, 28, 58, and 84, and ruminal fluid samples were collected on day 70. On day 90, the odor emissions from feces and urine were measured. On day 84, 12 lambs were slaughtered for the evaluation of carcass and meat quality. The final values for bodyweight, bodyweight gain, and feed efficiency of lambs fed the YS300 diet were 3.40%, 6.64%, and 6.17%, respectively, higher (p 600 diet. Additionally, the percentage of dressing, myofibril fragmentation index, and ruminal isovalerate percentage of lambs treated with YS600 were higher than those treated with YS300. Compared with the control, the addition of yucca reduced odor emissions from feces and urine. In conclusion, dietary YS300 had no additional benefits on growth rate, feed efficiency, and carcass traits, while dietary YS600 improved fecal and urinary odors

Effects of Rumex nervosus leaf powder supplementation on carcasses compositions, small intestine dimensions, breasts color quality, economic feasibility in broiler chickens

ABSTRACT: Carcass characteristics, product quality, and the conversion of feed into meat with higher performance and feasibility are important determinants of the profitability and sustainability of any poultry enterprise. The objective of this study was to investigate the potential effect of Rumex nervosus leaf powder (RNLP) on carcass composition, small intestine dimensions, breast color quality, and economic feasibility of Ross broiler chickens. A total of 122 broilers were randomly distributed evenly among 4 treatments (0, 1, 3, and 5 g RNLP/ kg diet, n = 5 replicates per treatment, with 6 broilers per replicate: 3 ♀ and 3 ♂). Performance and economic data were collected in each replicate during the experiment. One male bird from each replication was examined for other criteria on d 34. Results showed that broilers fed 3 g of RNLP had a higher eviscerated carcass weight and dressing percentage (P < 0.05) than the control. The RNLP-fed broilers had higher weights and thicknesses in the duodenum and jejunum of up to 5 g and in the ileum and overall small intestine of up to 3 g. Broilers fed the lowest levels of RNLP had the highest revenue and net gain and the lowest cost–benefit ratio compared with those fed the highest levels of RNLP. The results indicate that the addition of RNLP has a positive effect on carcass processing, the intestinal measurements, and profitability ratios of the broilers. The 1 g RNLP/kg feed is the recommended dose to increase productivity and economic profitability ratios per kilogram of meat

A comparative thermophysiological study between two purebred Saudi sheep under biometeorologically-simulated environment

Due to global warming, animal’s heat tolerance and adaptability characteristics to hot environmental conditions are attracting more research interest. The current experimental study was actually designed to evaluate and compare the heat tolerance efficiency of two purebred Saudi sheep when exposed to heat stress conditions under a biometeorologically-simulated environment similar to Kingdom of Saudi Arabia (KSA) semi-arid environment. A total of 20 healthy male growing lambs of Najdi and Naimi breed with an initial body weight of 24.71 ± 4.65 Kg and 4 month-old were used in a 2-phases experiment. During the preliminary phase (lasted for 3 weeks), lambs were placed under a stable thermoneutral condition. Meanwhile, simulation of the external environment was performed using climatic-controlled chambers during the experimental phase (lasted for 8 weeks). Several meteorological [ambient temperature (Ta), relative humidity (RH) and temperature humidity index (THI)] and thermophysiological [rectal temperature (Tr), skin temperature (Tsk), respiratory rate (RR), heat tolerance coefficient (HTC), adaptability coefficient (AC), internal (BTGin), external (BTGex) and total (BTGto) body thermal gradients] measurements were recorded at weeks 0, 4 and 8. The obtained meteorological data showed that the prevailed conditions in the climatic chamber exhibited (P < 0.05) elevated values compared to the chambers with control or thermoneutral conditions, which indicated that all lambs had undergone a different level of surrounding conditions, which was our goal in the first place. Notably, the obtained findings of all variables showed irrespective to the breed the same trend as they all were affected (P < 0.05) at the 4th weeks and slowly returned to their steady values by the 8th weeks, especially body temperatures. Under such hot climatic condition, lambs showed as well some breed difference, where Naimi lambs kept in eliciting (P < 0.05) higher values of RR, AC, and BTGto as well as lower values of HTC compared to their Najdi associates. In conclusion, the outcomes might collectively enable us to initially recommend selecting Najdi breed over Naimi breed for herding under the hot environmental conditions of KSA. However, identification of genes responsible for acquiring heat tolerance ability of Najdi compared to Naimi is highly recommended in future studies

Dietary Supplementation of Seaweed (Ulva lactuca) to alleviate the Impact of Heat Stress in Growing Lambs

Several environmental and nutritional management approaches have been used to mitigate heat stress and improve performance of farm animals in semi-arid and arid regions. The present study was designed with the intention to alleviate the negative effects of heat stress and to promote the performance of growing lambs reared under hot environmental conditions. The study was conducted on 18 male Naimey lambs with average body weight of 22.78±0.49 kg, and 4-5 months old. The animals were randomly divided into 3 equal groups (A, B and C), and fed diets containing different concentrations of seaweed (Ulva lactuca) for 90 days. Group A served as control and was offered diet containing 0.0% seaweed. Groups B and C served as treated groups and were offered diets containing 3.0 and 5.0% seaweed, respectively. Dietary inclusion of seaweed to the diet of growing lambs exposed to heat stress (max Ta 43.9oC, max RH 81.1%, max THI 84.6) neither influenced (P>0.05) the thermo-physiological parameters (rectal and skin temperatures), nor affected (P>0.05) the performance parameters (feed intake, body weight gain, feed conversion efficiency). Furthermore, dietary seaweed supplementation did not alter (P>0.05) blood constituents or blood antioxidant capacity. However, dietary seaweed supplementation significantly (P<0.05) reduced respiratory rate, and increased serum potassium concentration. Based on the data of the present study, seaweed (Ulva lactuca) supplementation to the diets of growing lambs reared under heat stress conditions did not show any indication of promoting their production performance or heat tolerance

Direct heat stress-induced effects on rumen fermentation characteristics and nutrients degradability in sheep pair-fed alfalfa hay

Aim of the study: To investigate the direct effect of heat stress on rumen fermentation characteristics and nutrients degradability of pair-fed rams to subsequently eliminate the confounding effects of dissimilar feed intake induced by heat stress exposure.Area of study: Saudi Arabia.Material and methods: Five rumen-cannulated desert rams (45 ± 1.63 kg body weight; 2–3 years of age) were placed individually in controlled climatic-chambers to be exposed to two successive periods. The 1st period was a control thermoneutral period (TN; 23.64 ± 0.14 °C; extended for 21 days) followed by a 2nd period of heat stress (HS; 44.26 ± 1.70 °C, for another 21 days). Each period was consisted of a temperature acclimation phase (7 days) and a data collection phase (14 days). Alfalfa hay was offered twice daily during both periods in a pair-fed manner (800 g DM per head and day).Main results: Exposing pair-fed desert rams to elevated ambient temperature had (p0.05) changes in their rectal temperature. Most of the rumen fermentation characteristics and nutrients degradability were not affected by HS (p>0.05). However, exposure to HS increased (p<0.05) pre-feeding rumen total volatile fatty acids concentrations, pre-feeding molar proportion of acetate, and post-feeding rumen osmolality.Research highlights: HS had no direct effect on post-feeding rumen fermentation characteristics and nutrients degradability in desert sheep. This implies that strategic approaches to mitigate the adverse effects of HS have to be directed towards promoting feed intake and nutrients utilization under such conditions