Differential Effects of Dietary Methionine Isomers on Broilers Challenged with Acute Heat Stress

Intestinal permeability, microbiota composition and expression of genes related to intestinal barrier function of broiler chickens fed different methionine sources supplemented at varying concentrations

Intestinal health of broiler chickens is influenced by the concentration of dietary amino acids but data are limited on the role of dietary methionine (Met). Two experiments were conducted to investigate the implications of different Met sources for performance, gut barrier function, and intestinal microbiota in broilers. In the first experiment, Ross 308 off-sex birds (n = 900) were assigned to 10 dietary treatments each replicated 9 times in a 35-day study. Three sources of Met included DL-Met, L-Met, or Met hydroxy analog free acid (MHA-FA), each supplemented at suboptimal (SUB) at 80%, adequate (ADE) at 100% and over-requirement (OVR) at 120% of the specifications against a deficient (DEF) diet with no added Met. The second experiment used 96 Ross 308 broilers in a 2 × 4 factorial arrangement. Four diets included 3 sources of Met supplemented at ADE level plus the DEF treatment. On d 17, 19, and 23, half of the birds in each dietary treatment were injected with dexamethasone (DEX) to induce leaky gut. In the first experiment, without an interaction, from d 0 to 35, birds fed DL-Met and L-Met performed similarly for BWG, feed intake, and FCR but birds fed MHA-FA had less feed intake and BWG (P < 0.05). At d 23, mRNA expression of selected tight junction proteins was not affected except for claudin 2. Ileal microbiota of DEF treatment was different from DL-MET or L-MET supplemented birds (P < 0.05). However, microbiota of MHA-FA treatments was only different at OVR from the DEF group. The abundance of Peptostreptococcus increased in DEF treatment whereas Lactobacillus decreased. In the second experiment, DEX independently increased (P < 0.001) intestinal permeability assayed by fluorescein isothiocyanate dextran, but diet had no effect. DL-Met and L-Met fed birds had a higher level of claudin 3 only in DEX-injected birds (P < 0.05). In conclusion, unlike the level of supplementation, DL-Met, L-Met, and MHA-FA were largely similar in their limited impacts on intestinal barrier function and gut microbiota in broilers.

Influence of Nano-Methionine supplementation in drinking water on growth performance, lipid metabolism, and related gene expression in broiler chicken

Objectives

The study aimed to determine how Nano-Methionine (Nano-Meth) affected growth, lipid metabolism, and relative gene expression for acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), growth hormone receptor (GHR), insulin-like growth factor receptor-1 (IGFR-1), myostatin (MSTN), and cholecystokinin (CCK) genes in broiler chickens.

Materials and Methods

A total of 100 1-day-old broilers were randomly assigned into 2 groups: 1) the control group received drinking water without any supplements, and 2) the Nano-Meth group received 10 ml/l of 5% Nano-Meth starting from 1 day old until 35 days old (the end of the experiment).

Results

Nano-Meth improved final body weight, weight gains, feed intake, and feed conversion ratio. Compared to the control group, Nano-Meth significantly lowered the serum levels of triglyceride, cholesterol, very low-density lipoprotein, and low-density lipoprotein in chickens. Nano-Meth significantly increased the serum levels of total protein, albumin, high-density lipoprotein, and glucose more than the control group. Nano-Meth lowered the mRNA gene expression of ACC, FAS, MSTN, and CCK but increased that of GHR and IGFR-1.

Conclusions

We concluded that supplementation with Nano-Meth enhances growth performance and decreases lipid accumulation in broiler chickens.

Exogenous emulsifiers and multi-enzyme combination improves growth performance of the young broiler chickens fed low energy diets containing vegetable oil

Objective

The present study examined the effects of exogenous emulsifiers and multi-enzyme supplementation into a low energy density diet on growth performance, visceral organ parameters, blood metabolites, ileal morphology, and nutrient digestibility in broiler chickens from hatch to 21 days.

Methods

One hundred and sixty-eight one-day-old Ross 308 broiler chickens were allocated in a completely randomized design to 24 pens and each pen was assigned to one of four dietary treatments to give six replications with seven chickens in a cage. Dietary treatments were: i) positive control with standard energy level (PC); ii) negative control with 100 kcal/kg lower energy of the standard level (NC); iii) NC diet supplemented 0.05% calcium stearoyl-2 lactylate as an emulsifier (NC+E); and iv) NC diet supplemented with both 0.05% calcium stearoyl-2 lactylate and 0.05% multi-enzyme (NC+E+M). Corn and soybean meal-based control diets containing vegetable oil were formulated to meet the Ross 308 nutrition specification. Chickens were fed ad-libitum with the treatment diets and sampling was conducted on day 21.

Results

Our results revealed that emulsifier and multi-enzyme supplementation into NC diets improved (p<0.05) feed efficiency of the broiler chickens compared to the broiler chickens fed NC diets from hatch to 21 days. Supplementation of emulsifier and multi-enzyme into NC diet improved (p<0.05) nutrient digestibility of the broiler chickens. However, emulsifier and multi-enzymesupplementation into diet did not influence (p>0.05) visceral organ weight, blood metabolites, and intestinal morphology in broiler chickens fed NC diets.

Conclusion

Supplementation of emulsifier and multi-enzyme in the NC diet would support improving growth performance in young broiler chickens with improved feed efficiency and increased nutrient digestibility thereby curtailing the negative impact of energy reduction in the diets.

Feeding a calcium-enriched fatty acid could ameliorate the growth performance of broilers under the chronic heat stress

The current study was conducted to evaluate the effect of calcium-enriched fatty acid supplementation on the growth performance, blood metabolites, intestinal morphology, carcass traits, and nutrient digestibility of broilers subjected to chronic heat stress. A total of 210 one-day-old broiler chicks (40.12 ± 0.25 g) were randomly allocated to one of five dietary treatments, to obtain six replicates per treatment. Broilers were subjected to chronic heat stress from day 21 to day 35, post-hatching, at 34°C for 9 h per day. The body weight (BW) and feed intake of the experimental broilers were recorded weekly, and the average daily gain (ADG) and feed conversion ratio (FCR) were calculated accordingly. Rectal temperature was measured to compare the basal body temperatures between individuals, and blood samples were collected on days 21 and 35 to evaluate basal body temperature, serum total cholesterol, and the triglyceride content of the broilers. On days 21 and 35, one broiler from each cage (n=6) was euthanized to measure carcass trait parameters, nutrient digestibility in digesta, and intestinal morphology. On days 14, 28, and 35, the broilers fed 2.0% calcium-enriched fatty acids had higher BW (p < 0.05) than those fed the other diets. However, no differences (p > 0.05) were found in the average daily feed intake (ADFI) between dietary treatments over the 35 experimental days. On the other hand, on day 21, post-hatching, the broilers fed the 2.0% calcium-enriched fatty acid diet had improved (p < 0.05) dietary feed efficiencies compared to the other treatments. On day 28, the broilers fed the 5.0% of calcium-enriched fatty acid diet also had higher (p < 0.05) dietary feed efficiencies than those fed with the other dietary treatments. No effects (p > 0.05) on carcass weight, nutrient digestibility, intestinal morphology, or blood parameters were found between broilers fed with dietary treatments. This study demonstrated that the inclusion of an additive, containing 2.0% calcium-enriched fatty acid, to broiler diet could ameliorate the negative growth performance of broilers; and no interaction (p > 0.05) was observed between the calcium-enriched fatty acid and nutrient digestibility, digestive anatomy, blood metabolism, and carcass traits of broilers subjected to chronic heat stress conditions for 35 days post-hatching.

Multi-carbohydrase application into energy and amino acid deficient broiler diets: A strategy to enhance performance of broiler chickens

The effect of Multi-Carbohydrase (MC) supplementation on growth performance, visceral organ weights, blood metabolites, jejunum morphology, nutrient digestibility, and carcass parameters of broiler chickens fed nutrient-deficient corn soybean-meal based diets containing high levels of non-starch polysaccharides from wheat and wheat by-products was investigated. A total of 378 one-day-old Ross 308 broiler chickens were randomly assigned to one of seven dietary treatments to give six replicates per treatment (nine birds per pen). Dietary treatments were as follows: (1) positive control (PC; commercial standard diet); (2) negative control 1 (NC-1; PC-120 kcal/kg metabolizable energy); (3) NC-2 (PC-3% standardized ileal digestibility [SID] amino acids). The remaining four dietary treatments were formulated with the addition of MC (MC; Superzyme-CS™) into two negative controls along with two supplementation levels of MC (i.e., 0.025% and 0.05%, respectively). Improved body weight, average daily gain, and feed conversion ratio (p < 0.05) were observed in broiler chickens fed a reduced energy diet supplemented with MC compared to birds fed NC-1 diet from days 1-35. Additionally, birds fed a reduced energy diet with 0.05% MC showed comparable (p > 0.05) growth performance with birds fed PC for 35-day post-hatch. Furthermore, the addition of MC into reduced amino acid diets improved (p < 0.05) growth performance. Broiler chickens fed MC supplemented nutrient-deficient diets showed a greater (p < 0.05) villus height to crypt depth ratio than birds fed diets without MC on days 21 and 35. Similarly, improved (p < 0.05) nutrient digestibility was observed in birds fed reduced energy diets supplemented with MC compared to birds fed NC-1 on days 21 and 35. Our results suggest that MC supplementation into reduced energy or reduced amino acid diets containing wheat and wheat by-products has the potential to improve growth performance and nutrient digestibility while maintaining healthier gut morphology in broiler chickens from 1 to 35 days of age.

Heat Stress-Mediated Activation of Immune-Inflammatory Pathways

Physiological changes in animals exposed to elevated ambient temperature are characterized by the redistribution of blood toward the periphery to dissipate heat, with a consequent decline in blood flow and oxygen and nutrient supply to splanchnic tissues. Metabolic adaptations and gut dysfunction lead to oxidative stress, translocation of lumen contents, and release of proinflammatory mediators, activating a systemic inflammatory response. This review discusses the activation and development of the inflammatory response in heat-stressed models.

Resveratrol sustains intestinal barrier integrity, improves antioxidant capacity, and alleviates inflammation in the jejunum of ducks exposed to acute heat stress

Resveratrol, a natural antioxidant, anti-inflammatory plant extract, was found to have a protective effect in poultry subjected to heat stress. In this study, we strove to characterize resveratrol on intestinal of duck exposed to acute heat stress and investigate the underlying mechanism. A total of 120 Shan-ma ducks (60 days old) were randomly divided into 2 groups. The control group was fed a basal diet, and the resveratrol group was fed a basal diet supplemented with 400 mg/kg resveratrol. Animals in 2 groups were kept at a temperature of 24°C ± 2°C for 15 d. Then, animals of both groups were placed in an artificial climate room at 39°C. Twelve ducks of each group were sacrificed for sampling at 0, 30, and 60 min, respectively. Results indicated that resveratrol increased the ratio of villus height to crypt depth, increased the number of goblet cells, and reduced the histopathological damage of jejunum caused by acute heat stress. Furthermore, the gene expression of heat shock proteins (HSP60, HSP70, and HSP90) and tight junction proteins (CLDN1 and OCLN) was significantly increased in the resveratrol group compared to that in the control groups. Simultaneously, resveratrol significantly activated the SIRT1-NRF1/NRF2 signaling pathways, improved ATP level of jejunum, and increased SOD and CAT antioxidant enzymes activities. In addition, we found that the NF-κB/NLRP3 inflammasome signaling pathways were repressed under acute heat stress. Meanwhile, supplement resveratrol further inhibited the NLRP3 inflammasome pathway, decreased protein level of NLRP3 and caspase1 p20, reduced the secretion of IL-1β. Taken together, our results indicate that resveratrol against the oxidative damage and inflammation injury in duck jejunum induced by heat stress via active SIRT1 signaling pathways.

In Ovo Injection of GABA Can Help Body Weight Gain at Hatch, Increase Chick Weight to Egg Weight Ratio, and Improve Broiler Heat Resistance

Simple Summary

Heat stress is a vital issue that causes severe losses to the poultry industry. A partly developed thermoregulatory mechanism during the embryonic phase is emphasized to manipulate embryos for achieving thermotolerance during rearing. The present study was conducted firstly to standardize the dosage for an in ovo manipulation, and the selective dose was used to evaluate its effects on early-age heat-stressed (HS) broilers. HS induces cholesterol while an antioxidant acts as a first line of defense under stress. However, 5% GABA supplementation had a higher hatchling weight and chick weight to egg weight ratio (CWEWR). We selected a 10% GABA dosage for HS studies due to its higher antioxidants and lower cholesterol values in hatchlings. In ovo, 10% GABA supplementation significantly increased total antioxidant capacity and reduced malondialdehyde levels, hepatic mRNA levels of HSP70, FAS, and L-FABP in broilers when subjected to HS (38 ± 1 °C; 3 h) at ten days of age. This indicates that an in ovo GABA injection improves CWEWR and antioxidant status at hatch, and creates thermotolerance by increasing antioxidant production and downregulating the expression of HSP70 and fatty acid metabolism genes in HS chicks.

Abstract

The aim of this study was to explore the outcomes of an in ovo GABA injection in broilers challenged with HS. In Experiment 1, 210 Arbor Acres eggs were allocated to five treatments: no-injection, and in ovo injection of 0.6 mL of 0%, 5%, 10%, or 20% of GABA. Hatchling weight and CWEWR were significantly increased in the 5% GABA group. In ovo, injection of 10% GABA solution caused a significant decrease in plasma cholesterol and increased plasma total antioxidant capacity of hatchlings. Experiment 2 was conducted with 126 fertile Arbor Acres eggs distributed into one of two groups. At 17.5 days of incubation, one received no injection, and the other was fed 0.6 mL of 10% GABA. On day 10, one subgroup (4 replicates * 3 birds) from each treatment was submitted to HS (38 ± 1 °C for 3 h) while the other was kept at a thermoneutral temperature (29 ± 1 °C). An in ovo injection of GABA significantly increased total antioxidant capacity, but reduced malondialdehyde levels, hepatic mRNA levels of HSP70, FAS, and L-FABP with HS. In conclusion, an in ovo GABA injection improves CWEWR and antioxidant status at hatch, and enhances antioxidant status while downregulating the expression of HSP70 and fatty acid metabolism-related genes in young chicks under HS.

Multi-tissue transcriptomic analysis reveals that L-methionine supplementation maintains the physiological homeostasis of broiler chickens than D-methionine under acute heat stress

The objective of this study was to compare the effects of supplementation with two methionine isoforms, L-methionine (L-Met) or D-methionine (D-Met), on transcriptome expression in broiler chickens under acute heat stress. A total of 240 one-day-old chicks were randomly assigned to one of four treatments in a 2 × 2 factorial arrangement: thermo-neutral vs. acute heat-stress and L-Met vs. D-Met supplementation. On day 14, the heat-stressed group was exposed to 32°C for 5 h, while the others remained at 25°C. Six chicks were randomly selected per treatment and total RNA was isolated from whole blood, ileum, and liver tissues. Two RNA samples from each tissue of each treatment group were randomly selected and pooled in equal amounts. A total of 1.87 billion raw reads obtained from 36 samples (four treatments × three tissues × three composited replicates) were mapped to the reference genome build (Gallus_gallus-5.0) and used to identify differentially expressed genes (DEGs) using DESeq2. Functional enrichment of DEGs was tested using DAVID. Comparing the two isoforms of supplemented methionine, two, three, and ten genes were differentially expressed (> 1 or < -1 log₂ fold change) in whole blood, ileum, and liver, respectively. A total of 38, 71, and 16 genes were differentially expressed in response to the interaction between heat stress and Met isoforms in the blood, ileum, and liver, respectively. Three-tissue-specific DEGs were functionally enriched for regulation of cholesterol homeostasis and metabolism, glucose metabolism, and vascular patterning. Chicks fed with L-Met had lower immune (e.g., IL4I1 and SERPINI1) and intestinal angiogenic responses (e.g., FLT1 and FGD5), and stable glucose and lipid metabolism (e.g., PCK1 and LDLR) under heat stress conditions. In conclusion, unlike D-Met, L-Met supplementation seems to help maintain physiological homeostasis and enhances cellular defense systems against external stresses like high environmental temperature.

The impact of different levels of L-methionine (L-Met) on carcass yield traits, serum metabolites, tibial characters, and profitability of broilers fed conventional diet

Objectives:

The experiment was undertaken to investigate the performances of broilers with respect to meat yield traits, leg bone quality, blood metabolites, and economic profitability fed conventional diets supplemented with L-methionine (L-Met).

Materials and methods:

Day-old broiler chicks (n = 144) of either sex were used to conduct the experiment from d1 to 33 days in a battery cage rearing system. Birds were distributed randomly into four dietary treatments, i.e., D₀ (DL-Met), D₁ (0.20% L-Met), D₂ (0.25% L-Met), and D₃ (0.30% L-Met) in a completely randomized design. Broiler chicks were fed complete starter ration for the first 2 weeks and then test diets were supplied ad libitum from d15 to 33 days. All the formulated rations had the same calorie and proteinous values. Similar housing, feeding, and rearing management were provided to the birds for all the experimental period. Data on carcass yield traits, such as dressing %, thigh, breast, back, drumstick, shank, neck, and wing weights, etc, were measured on the last day of the trial. Blood serum profile (total protein, glucose, albumin, uric acid, creatinine, and triglycerides), right tibial bone traits (bone weight, bone width), and mineral concentrations (Ca% and P%) were also assessed on the last day of the experiment. The economic profitability of broilers fed on the L-Met diet was also measured in this study.

Results:

The results revealed that except for dressing % (p < 0.05) and back weight (p < 0.01); all other meat characteristics measured this study were found similar (p > 0.05) between treatments. The highest dressing % and back weight were observed in the D₃ group and the lowest being in D0. Blood serum metabolites did not differ (p > 0.05) among treatments. Leg bone traits of broilers were found similar (p > 0.05) between treatments. Higher profit (p < 0.01) and lower production cost (p < 0.05) were observed in the birds fed the D₃ diet than other treatments.

Conclusion:

It can be inferred that broilers might show improved dressed yield and profitable broiler production fed on L-Met supplemented diet (D₃).