Hepatic heat shock proteins, antioxidant-related genes, and immunocompetence of heat-stressed broilers in response to short periods of incubation during egg storage and thermal conditioning

Impact of in ovo feeding of grape pomace extract on the growth performance, antioxidant status, and immune response of hatched broilers

Delivering natural antioxidants via in ovo feeding holds promise for enhancing the antioxidant status and performance of chickens. Therefore, The objective of this study was to evaluate the impacts of in ovo feeding during early embryonic development using grape pomace extract as a natural antioxidant on hatchability, productive performance, immune response, and antioxidant status in broilers. A total of 900 fertile broiler eggs from the Arbor Acres strain were utilized. Each egg was individually weighed, with egg weights ranging from 61.88 ± 3 g. On the 17.5th d of incubation (DOI), the fertile eggs were divided into 6 groups. The first treatment group was untreated and designated as the control (C). The second group was the sham group (Sh), receiving a simulated injection. The third group, designated as the vehicle group (V), was injected with 100 µl of dimethyl sulfoxide (DMSO). The fourth group received an injection of 100 µL of grape pomace dissolved in DMSO at a concentration of 2 mg (T2). Similarly, the fifth and sixth groups were injected with 100 µL of grape pomace dissolved in DMSO at concentrations of 4 mg and 6 mg, (T4), (T6) respectively. Subsequently, all groups were raised under uniform conditions in terms of management, environment, and nutrition till 5 wk of age. The grape pomace extract (GPE), obtained is rich in total phenolic content (16.07 mg/g), total flavonoid content (7.42 mg/g), and total anthocyanin (8.37 mg/g). Grape pomace extract has exhibited significant antioxidant properties as evidenced by its effectiveness in DPPH scavenging and reducing power assays. Significant improvements in body weight at hatch were observed with in ovo feeding of grape pomace extract, particularly at the 4 mg level, surpassing the effectiveness of the 2 mg and 6 mg grape pomace levels, and this enhancement in body weight continued until the age of 5 wk. GPE injection also led to a significant reduction in cholesterol levels, with the lowest levels recorded for the T4 group. Plasma total Antioxidant Capacity (TAC) levels were significantly elevated in groups treated with T4, T6, and T2 compared to the control group. Conversely, the control group showed a significant increase (P < 0.01) in plasma malondialdehyde (MDA) levels. The immune response of hatched chicks from grape pomace extract-injected groups, especially the T4 group, exhibited improvement through increased IgM and IgG. These findings demonstrate that in ovo feeding of GPE, particularly at a dosage of 4 mg, enhances growth performance, immune response, and antioxidant status in hatched chicks. Thus, administering natural antioxidants, such as grape pomace extract, to developing broiler embryos via in ovo feeding could serve as a valuable strategy for enhancing the subsequent post-hatch productive performance, as well as bolstering the antioxidant and immunological status of broiler chicks.

Dietary pterostilbene exerts potential protective effects by regulating lipid metabolism and enhancing antioxidant capacity on liver in broilers

Intensive breeding of broilers met the increasing demands of human for broiler products, but it raised their increased susceptibility to various stressors resulting in the disorder of lipid metabolism. Pterostilbene, the methoxylated analogue of resveratrol, exhibits astonishing functions of antioxidant, anti-inflammatory and glycolipid regulatory. The study aimed to elucidate the protective effects of pterostilbene on broiler liver and to explore the potential mechanisms. A total of 480 one-day-old male Arbor Acres (AA) broilers were randomly divided into four groups: the control group (basal diet) and pterostilbene groups (PT200, PT400, and PT600 feeding with basal diet containing 200, 400 and 600 mg/kg pterostilbene, respectively). The results showed that the dietary pterostilbene supplementation significantly improved the ADG of broilers. Dietary pterostilbene supplementation regulated the expression levels of the genes Sirt1 and AMPK and the downstream genes related to lipid metabolism to protect liver function and reduce lipid accumulation in broilers. Dietary pterostilbene supplementation upregulated the expression levels of the Nrf2 gene and its downstream antioxidant genes (SOD, CAT, HO-1, NQO-1, GPX) and phase II detoxification enzyme-related genes (GST, GCLM, GCLC). Collectively, pterostilbene was confirmed the positive effects as a feed additive on lipid metabolism and antioxidant via regulating Sirt1/AMPK and Nrf2 signalling pathways in broilers.

Growth performance, histological and physiological responses of heat-stressed broilers in response to short periods of incubation during egg storage and thermal conditioning

The short periods of incubation during egg storage (SPIDES) method enhances the quality of chicks and improves hatching rates. Additionally, embryonic thermal conditioning (TC) is a technique used to enhance thermotolerance in birds. Previous studies have evaluated the effects of SPIDES and embryonic TC separately. Yet, our hypothesis postulated that a synergistic effect could be achieved by integrating TC and SPIDES, thereby enhancing the broilers' resilience to thermal stress. We conducted an experiment involving 800 Ross broiler eggs, divided into two groups. The first group, referred to as S0, was maintained under standard storage room conditions and acted as our control group. The second group, known as S1, underwent a process called SPIDES for 5 h at a temperature of 37.8 ± 0.1 °C, on three occasions: days 5, 10, and 15 following egg collection. Upon reaching the 14th day of incubation (DOI), each of these primary groups was randomly subdivided into two equal subgroups. The control subgroup, designated as TC0, remained in the usual incubation conditions. Meanwhile, the other subgroup, TC1, was subjected to prenatal heat conditioning at a temperature of 39.5 ± 0.1 °C for 6 h per day, commencing on the 14th embryonic day (E) and extending until the 18th embryonic day (E). This experimental setup resulted in four distinct experimental subgroups: S0TC0, S1TC0, S0TC1, and S1TC1. The findings indicated that the combined application of SPIDES and TC had a significant positive effect on chick performance after hatching. Specifically, the (S1TC1) group exhibited the heaviest live body weight (LBW) and body weight gain (BWG) at the marketing age in comparison to the other groups. Furthermore, both SPIDES and TC had a positive influence on the relative weights of breast muscles and their histological measurements. The (S1TC1) group displayed significantly higher values in terms of the relative weight of breast muscles and the number of myocytes. In conclusion, SPIDES and TC have beneficial effects on pre- and post-hatch characteristics of broiler chicks up until the marketing age. Additionally, TC techniques improve chick performance, particularly under conditions of heat stress, and enhance the yield of breast muscle in later stages of life.