Antioxidative and anti-inflammatory effects of vitamin C on the liver of laying hens under chronic heat stress

Abstract

In this study, we investigated the therapeutic effect and mechanism of action of vitamin C on chronic heat stress (CHS)-induced liver oxidative damage and inflammation in laying hens. The thermoneutral control group (TN group) was kept at a constant temperature of 22 ± 1°C, while the chronic heat stress group (CHS group) and the vitamin C supplemented group (HSV group) were exposed to heat stress (HS) (36 ± 1°C, 8 h/d). The TN and HS groups were fed the basic diet at will, and the HSV group was supplemented with 300 mg/kg of vitamin C on top of the basic diet. The experimental results showed a significant improvement in body weight and feed intake in the HSV group compared to the HS group. A significantly lower pH and higher HCO3- and PCO2 levels were observed in the HSV group compared to the CHS group. As laying hens were supplemented with vitamin C, serum malondialdehyde (MDA) level was declined, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were increased, and total antioxidant capacity (T-AOC) was increased. Further, CHS induced an increase in the expression of inflammation-related genes and a decrease in the expression of antioxidant-related genes. In contrast, the addition of vitamin C reversed the effects of CHS, resulting in an increase in the expression of antioxidant-related genes and a decrease in the expression of inflammation-related genes. In conclusion, vitamin C can effectively alleviate CHS-induced acid-base imbalance in body fluids of laying hens and the oxidative damage and inflammatory response caused to the liver. Therefore, vitamin C can be used clinically as an effective drug to alleviate chronic heat stress in laying hens. This experiment provides clinical evidence and theoretical basis for the use of vitamin C as an effective drug to alleviate chronic heat stress in laying hens.

Stress-Related Gene Expression in Liver Tissues from Laying Hens Housed in Conventional Cage and Cage-Free Systems in the Tropics

“…In laying hens exposed to stress, egg production could be affected by the liver response which modulates the metabolism to maintain homeostasis [28]. In addition, the higher SD has been associated with increased mortality and disturbances, primarily due to heat stress, impacting the liver through oxidative stress and infammation [29][30][31]. Several studies have suggested that stress can be induced by densities lower than 465 cm 2 /hen, whereas in our study, the density was 450 cm 2 /hen in CC systems [25,32].…”

A mixed antioxidant supplement improves cognitive function, and coordination in aged mice

“…For example, vitamin C was reported to exert an anti-inflammatory effect in the liver against heat stress. (36) Since the mice in the present study were subjected to training, heat stress may play a major role in triggering liver inflammation. It has also been reported that dipeptides of L-glutamine and L-alanine exert antioxidant and antiinflammatory effects in the liver.…”

Translucent eggs of laying hens: a review

“…Controlled environmental systems have reduced the incidence of acute heat stress in chickens, causing chronic heat stress to predominate. The optimal temperature range for poultry production is 19 to 22°C ( Du et al, 2022 ). Beyond this range, egg weight, eggshell weight, and eggshell thickness will all decrease significantly ( Mashaly et al, 2004 ).…”

“…At 34°C, inflammatory responses in chickens increase, resulting in decreased egg production and feed intake, as well as intestinal morphology damage and subsequent intestinal health issues ( Deng et al, 2012 ). Heat stress is a primary source of oxidative stress, primarily affecting the liver ( Du et al, 2022 ). The main sources of calcium for eggshell formation are dietary calcium absorbed from the intestine and calcium released from the medullary bone.…”