Effects of Dietary Supplementation with Epigallocatechin Gallate on Meat Quality and Muscle Antioxidant Capacity of Broilers Subjected to Acute Heat Stress

The effect of epigallocatechin gallate on laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of laying ducks reared in high temperature condition

Epigallocatechin gallate (EGCG) is a main component in green tea extract, which possesses multiple bioactivities. The present research studied the effects of EGCG on the laying performance, egg quality, immune status, antioxidant capacity, and hepatic metabolome of Linwu laying ducks reared under high temperature. A total of 180 42-w-old healthy Linwu laying ducks were allocated into control or EGCG-treated groups. Each treatment had 6 replicates with 15 ducks in each replicate. Diets for the two groups were basal diets supplemented with 0 or 300 mg/kg EGCG, respectively. All ducks were raised in the high temperature condition (35 ± 2 °C for 6 h from 10:00 to 16:00, and 28 ± 2 °C for the other 18 h from 16:00 to 10:00 the next day) for 21 days. Results showed that EGCG increased the egg production rate (p = 0.014) and enhanced the immunocompetence by improving serum levels of immunoglobulin A (p = 0.008) and immunoglobulin G (p = 0.006). EGCG also fortified the antioxidant capacity by activating superoxide dismutase (p = 0.012), catalase (p = 0.009), and glutathione peroxidase (p = 0.021), and increasing the level of heat-shock protein 70 (p = 0.003) in laying ducks' liver. At the same time, hepatic metabolomics result suggested that EGCG increased the concentration of several key metabolites, such as spermidine (p = 0.031), tetramethylenediamine (p = 0.009), hyoscyamine (p = 0.026), β-nicotinamide adenine dinucleotide phosphate (p = 0.038), and pantothenic acid (p = 0.010), which were involved in the metabolic pathways of glutathione metabolism, arginine and proline metabolism, β-alanine metabolism, and tropane, piperidine, and pyridine alkaloid biosynthesis. In conclusion, 300 mg/kg dietary EGCG showed protection effects on the laying ducks reared in high temperature by improving the immune and antioxidant capacities, which contributed to the increase of laying performance of ducks. The potential mechanism could be that EGCG modulate the synthesis of key metabolites and associated metabolic pathways.

Green tea catechin prevents oxidative stress-regulated autophagy and apoptosis signaling, and inhibits tenderness in postmortem bovine longissimus thoracis et lumborum muscle

Although green tea catechin has been reported to be an antioxidant and preservative in meat, the extent to which it affects the tenderization of bovine muscle remains largely unknown. This study seeks to evaluate the effect of catechin on the interplay between apoptosis and autophagy, and subsequently, the development of bovine muscle tenderness. The results indicate that catechin significantly alleviated oxidative stress. A concomitant reduction of autophagic markers LC3-II/LC3-I ratio, Beclin-1, and Atg7 levels were caused by catechin. Besides, aforementioned autophagy inhibition was further augmented by PI3K/Akt/mTOR activation. Additionally, catechin protected against mitochondrial dysfunction and inhibited mitochondria-dependent caspase apoptosis pathway. Furthermore, there was a reciprocal inhibition between autophagy and apoptosis. Ultimately, tenderness at 24 and 120 h, an increase in the gap between muscle fiber bundles, and disintegration of myofibrillar architectures were all inhibited by catechin. Therefore, despite alleviating oxidative stress, catechin may hamper tenderization pattern of postmortem bovine muscle.

Effects of Clostridium butyricum on growth performance, meat quality, and intestinal health of broilers

This study investigated the effects of Clostridium butyricum on the growth performance, meat quality and intestinal health of broilers. A total of 800 one-day-old male Arbor Acres broilers were randomly assigned to two groups with 16 replicates of 25 broilers per group and fed with a basal diet (CON) or a basal diet supplemented with 1.5 × 10⁹ cfu/kg C. butyricum and 5 × 10⁸ cfu/kg C. butyricum at 1-21 d and 22-42 d, respectively (CB). The results indicated that C. butyricum significantly increased the final body weight, average daily gain at 1-42 d in the growth performance of broilers (P < 0.05). Moreover, C. butyricum significantly increased a 24 h * value and pH_24h value of breast meat but reduced the drip loss and shear force (P < 0.05). Regarding serum antioxidant indices, C. butyricum significantly increased the total superoxide dismutase (T-SOD) and total antioxidative capacity activities and reduced the malondialdehyde content (P < 0.05). Furthermore, the broilers in the CB demonstrated an increase in jejunal lipase and trypsin activities, villus height (VH) and VH-to-crypt depth ratio at 42 d compared with those in the CON (P < 0.05). C. butyricum also upregulated the intestinal mRNA levels of zonula occludens-1, nuclear factor erythroid 2-related factor 2 (Nrf2), SOD1 and interleukin-10 in the jejunal mucosa (P < 0.05), but it downregulated the mRNA levels of nuclear factor kappa B (NF-κB) and tumor necrosis factor-α (P < 0.05). These results indicate that C. butyricum can improve the growth performance and meat quality of broilers. In particular, C. butyricum can improve the intestinal health of broilers, which is likely to be related to the activation of the Nrf2 signaling pathway and inhibition of the NF-κB signaling pathway.

An Encapsulated Organic Acid and Essential Oil Mixture Improves the Intestinal Health of Weaned Piglets by Altering Intestinal Inflammation and Antioxidative Capacity

This study investigates the effects of an encapsulated organic acid and essential oil mixture (OAEO) on the growth performance, immuno-antioxidant capacity and intestinal health of weaned piglets. In total, 120 weaned piglets (23 days of age; 6.96 ± 0.08 kg) were randomly allotted to four treatments (six replicates/group; five piglets/replicate): the control group (CON) was fed the basal diet (BD), the antibiotic growth promoters group (AGP) received the BD with 20 mg/kg colistin sulphate and 10 mg/kg bacitracin zinc, and OAEO1 and OAEO2 were fed the BD with 1000 mg/kg and 2000 mg/kg OAEO, respectively. The trial lasted 21 days and then one piglet per replicate was selected for sample collection. OAEO increased the average daily gain, spleen index, serum interleukin (IL)-10, immunoglobulin (Ig) G and IgA levels; serum superoxide dismutase and glutathione peroxidase (GPX) activities; and jejunal villus height (VH), VH/crypt depth, goblet cell number, and amylase and trypsin activities (p < 0.05) compared with CON but reduced the diarrhea rate, serum tumor necrosis factor (TNF)-α, malondialdehyde (MDA), and D-lactic acid contents and diamine oxidase (DAO) activity (p < 0.05). OAEO also increased the jejunal zonula occludens-1, occludin, claudin-1, mucin-2, nuclear factor erythroid 2-related factor 2 (Nrf2), GPX and IL-10 mRNA levels, GPX activity and IL-10 content (p < 0.05) compared with CON but reduced jejunal MDA, IL-1β and TNF-α contents and Toll-like receptor (TLR) 4, nuclear factor (NF)-κB and TNF-α mRNA levels (p < 0.05). In addition, AGP increased ADG, serum IgA level and GPX activity, jejunal trypsin activity and IL-10 content and mRNA level (p < 0.05) compared with CON but reduced the serum TNF-α content and DAO activity and jejunal NF-κB mRNA level (p < 0.05). Overall, OAEO as an alternative to AGP improved the growth performance, immuno-antioxidant status and gut health of weaned piglets partly via activating the Nrf2 signaling pathway and suppressing the TLR4/NF-κB signaling pathway.

Resveratrol Attenuates Heat Stress-Induced Impairment of Meat Quality in Broilers by Regulating the Nrf2 Signaling Pathway

Studies have indicated that dietary resveratrol (RES) improves the meat quality of broilers subjected to heat stress (HS), but the mechanism of action remains unclear. Therefore, the main purpose of this study was to investigate the effect of RES on meat quality, muscle antioxidant status, and its mechanism of action in broilers under HS. A total of 162 male AA broilers at 21 days old with similar weight were randomly assigned to 3 treatment groups with 6 replicates each. The control group (ambient temperature: 22 ± 1 °C) and HS group (ambient temperature: 33 ± 1 °C for 10 h a day from 8:00 to 18:00 and 22 ± 1 °C for the remaining time) were fed a basal diet and the HS + RES group was fed a basal diet with 400 mg/kg RES. The feeding was conducted for 21 continuous days. The results indicated that HS decreased final body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), breast and leg muscle yield, a*24h, pH24h, the activities of catalase (CAT), glutathione S-transferase (GST) and glutathione peroxidase (GSH-Px), and mRNA levels of nuclear factor erythroid 2−related factor 2 (Nrf2), heme oxygenase-1 (HO-1), NADPH quinone oxidoreductase 1 (NQO1), and GSH-Px (p < 0.05). HS also increased b*45min, L*24h, drip loss, malondialdehyde (MDA) content, and kelch-like epichlorohydrin-associated protein 1 (Keap1) mRNA level (p < 0.05). Compared with the HS group, the HS + RES group exhibited a higher ADG, breast and leg muscle yield, a*24h, pH24h, activities of GST and GSH-Px, and mRNA levels of Nrf2, HO-1, and NQO1 but had lower drip loss and Keap1 mRNA level (p < 0.05). RES can improve meat quality and the muscle antioxidant ability of heat-stressed broilers by activating the Nrf2 signaling pathway.