Antioxidants status and physiological responses to early and late heat stress in two rabbit breeds

Abstract

Early life heat stress negatively affects rabbit production and well‐being. However, the physiological response to acute heat stress in later life is not clearly defined. The present study aims to investigate the effects of early and late heat stress at 36°C on some blood constituents, antioxidant enzymes activity in the blood, and muscle in New Zealand white and Baladi Black rabbits. A total of sixty post‐weaning rabbits of each breed were randomly divided into two groups; control groups (NZWC and BBC) and early heat‐stressed groups for six hours at 36 ± 1°C and 62% relative humidity (RH) (NZWT and BBT groups). After heat stress, six rabbits from each group were slaughtered for blood and muscle tissue collection. The surviving rabbits were kept at 28 ± 1°C and 40% RH till 13 weeks of age. At the end of 13 weeks, all rabbits were exposed to late heat stress as precious described to perform four groups: single late stressed groups; NZWC2, BBC2, and double stressed groups; NZWT2 and BBT2. After late heat stress, six rabbits from each group were slaughtered for blood and muscle tissue collection. The early and late heat stress caused a significant reduction in the blood creatine kinase, lactate dehydrogenase, and high‐density lipoprotein and antioxidant enzymes' activity in blood and muscle of both NZW and BB rabbits compared with the control groups. While, the blood total cholesterol, triglycerides, total lipids levels, and lipid peroxidation activity in blood and muscle were significantly increased due to the early and late heat‐stressed both breeds compared with the control groups. It could be concluded that the early heat stress at 36°C has negative effects on several physiological indicators and antioxidant activities in the blood and muscle of NZW and BB rabbits.

Seasonal Variations in Production Performance, Health Status, and Gut Microbiota of Meat Rabbit Reared in Semi-Confined Conditions

“…Under thermoneutral conditions, antioxidative enzymes such as SOD and GSH are capable of scavenging reactive oxygen species to modulate redox status and dynamic balance. In agreement with our findings, both Saghir et al and Madkour et al pointed out that the rabbits’ plasma concentrations of SOD and GSH declined with the increasing house temperature while the level of MDA was elevated, which was linked to progressive oxidative stress [ 27 , 28 ]. Simultaneously, considering the intimate relationship between oxidative stress and inflammation responses, we noted that the levels of pro-inflammatory cytokines such as IL-1α, IL-1β, and IL-2 were increased.…”

The Influence of a Nanoemulsion of Cardamom Essential Oil on the Growth Performance, Feed Utilization, Carcass Characteristics, and Health Status of Growing Rabbits under a High Ambient Temperature

“…Our study exhibited noteworthy decreases in the concentrations of pro-inflammatory cytokines (IFN-γ and IL-4) in the NCEO-supplemented rabbits compared to the control, indicating the potent anti-inflammatory activities of NCEO. On the other hand, the dietary treatment resulted in a significant increase in the concentration of NO, which is a small molecule that plays an indispensable role under physiological concentrations in defense against pathogens and thermos-tolerance during heat stress, as it has a decisive role in the vasodilation of the blood vessels of the skin [ 48 , 56 , 57 ]. Moreover, mounting evidence suggests that NO plays other roles in neurotransmission and immune regulation [ 7 , 57 ].…”

Ramifications of Heat Stress on Rabbit Production and Role of Nutraceuticals in Alleviating Its Negative Impacts: An Updated Review

“…Similarly, several studies revealed that the plasma concentration of GSH-Px, SOD, and CAT was significantly minimized, while the plasma level of MDA was elevated in heat-stressed rabbits [84,85]. Likewise, Madkour et al [86] observed that HS at 36 • C lessened the amounts of SOD, GSH, and CAT, and elevated the MDA concentration in the blood plasma and muscle of broiler rabbits. Bai et al [79] postulated that the plasma total antioxidant capacity (TAC) concentration was reduced in growing rabbits under HS conditions.…”

“…Additionally, in fattening rabbits exposed to HS, the serum lysosome activity and nitric oxide levels were reduced [34]. Moreover, HS disturbed the equilibrium between anti-inflammatory and pro-inflammatory cytokines [34], which might be connected with a progressive inflammation response [86]. Abdel-Latif et al [39] observed that HS had a negative influence on IFN-γ, TNF-α, and heat shock protein 70 (HSP70) expression leading to affect the infiltration of regulatory T cells adversely and NK cells in New Zealand White (NZW) growing rabbits.…”