Effects of Methionine Supplementation in Low-Protein Diets and Subsequent Re-feeding on Growth Performance, Liver and Serum Lipid Profile, Body Composition and Carcass Quality of Broiler Chickens at 42 Days of Age

Relative biological efficacy of methionine hydroxy analogue-free acid compared to dl-methionine in the broiler chickens

BACKGROUND

In the broiler's diets based on corn-soya bean meal, methionine (Met) and cystine (Cys), known as sulphur amino acids (SAAs), are the first limiting indispensable amino acids because of their limited presence, which are supplemented with different synthetic sources. Evaluation of the biological effectiveness of these sources can be important in their correct replacement, especially in the starter and growth diets.

OBJECTIVES

The current study was done to assess the relative biological efficacy (RBE) of liquid Met hydroxy analogue-free acid (MHA-FA) in comparison with dl-Met (dl-Met) based on broiler performance traits at different levels of digestible SAA in the 1-11 (starter) and 11-25 (grower) days of age periods.

METHODS

Two experiments were developed with treatments consisting of a basal diet without Met addition that met the nutrient and energy requirements of broilers with the exception of SAAs (Met + Cys) and five increasing Met doses for both sources (dl-Met and/or MHA-FA), resulting in digestible SAA concentrations from 0.62% to 1.02% of diet in the starter period (Trial 1) and 0.59% to 0.94% of diet in the grower period (Trial 2). The multi-linear regression model and slope ratio method were employed to calculate the RBE of MHA-FA compared with dl-Met for measured variables.

RESULTS

In both experiments, the results obtained during the starter and grower periods with the different Met supplementations show significant growth responses to digestible SAAs levels. By increasing dietary dl-Met and/or MHA-FA levels, the growth performance traits and immune responses were improved (quadratic; p < 0.05). The RBE of MHA-FA compared to dl-Met on an equimolar basis was estimated 66%-89% (59%-79% on a weight-to-weight basis).

CONCLUSIONS

It is concluded that the RBE of MHA-FA in comparison with dl-Met depends on broiler chicken age and what attribute is being evaluated.

Comparative Analysis of Different Proteins and Metabolites in the Liver and Ovary of Local Breeds of Chicken and Commercial Chickens in the Later Laying Period

The liver and ovary perform a vital role in egg production in hens. In the later laying period, the egg-laying capacity of female hens, particularly that of local breeds, declines significantly. Hence, it is essential to study the features and conditions of the ovary and liver during this period. In this research, we characterized the proteins and metabolites in the liver and ovary of 55-week-old Guangyuan gray chickens (Group G) and Hy-Line gray chickens (Group H) by using liquid chromatography chip/electrospray ionization quadruple time-of-flight/mass spectroscopy (LC-MS/MS). In total, 139 differentially expressed proteins (DEPs) and 186 differential metabolites (DMs) were identified in the liver, and 139 DEPs and 36 DMs were identified in the ovary. The upregulated DEPs and DMs in both the liver and ovary of Group G were primarily enriched in pathways involved in amino acid and carbohydrate metabolism. This suggests that energy metabolism was highly active in the Guangyuan gray chickens. In contrast, the upregulated DEPs and DMs in Group H were mainly enriched in pathways associated with lipid metabolism, which may explain the higher egg production and the higher fatty liver rate in Hy-Line gray hens in the later laying period. Additionally, it was found that the unique protein s-(hydroxymethyl) glutathione dehydrogenase (ADH4) in Group G was implicated in functions such as fatty acid degradation, glycolysis, and pyruvate metabolism, whereas the unique proteins, steroid sulfatase (STS), glucosylceramidase (LOC107050229), and phospholipase A2 Group XV (PLA2G15), in Group H were involved in the metabolism of steroid hormones and glycerol phosphate. In conclusion, variations in how carbohydrates, lipids, and amino acids are processed in the liver and ovary of local breeds of chicken and commercial hens towards the end of their laying period could explain the disparities in their egg production abilities.

Effects of organic zinc on production performance, meat quality, apparent nutrient digestibility and gut microbiota of broilers fed low-protein diets

The high cost of feed and nitrogen pollution caused by high-protein diets have become major challenges restricting sustainable development in China's animal husbandry sector. Properly reducing protein levels and improving protein utilization in feed are effective approaches to solving this problem. To determine the optimal dose of methionine hydroxyl analogue chelated zinc (MHA-Zn) in broiler diets with a 1.5% reduction in crude protein (CP), a total of 216 1-day-old broilers were randomly assigned into 4 groups (each group consisted of 3 replications with 18 broilers per replicate), and growth and development indexes were assessed after 42 days. The broilers in control group were fed a basic diet, whereas those in the three test groups were fed diets with a 1.5% reduction in CP. The results showed no significant difference in the edible parts of broilers between low-protein (LP) diet group (90 mg/kg MHA-Zn) and normal diet group (p > 0.05), and adding 90 mg/kg MHA-Zn to LP diet significantly improved ileum morphology and apparent total tract digestibility (ATTD) of nutrient (p < 0.01; p < 0.05). A 16S rRNA sequencing analysis indicated that supplementing the LP diet with 90 mg/kg MHA-Zn was adequate for production performance of broilers and promoted beneficial bacteria in the cecum (Lactobacillus, Butyricoccus, Oscillospira, etc.) (p < 0.01). In summary, adding an optimal dose of organic zinc (90 mg/kg MHA-Zn) in low protein diets led to enhanced production performance of broilers and optimized cecum microbiota. Additionally, the reduction of crude protein consumption in broiler production proved to be a cost-effective measure, while also mitigated nitrogen pollutant emissions in the environment.

Methionine Deficiency Affects Liver and Kidney Health, Oxidative Stress, and Ileum Mucosal Immunity in Broilers

Methionine (Met) is the first limiting amino acid in broiler diets, but its unclear physiological effects hamper its effective use in the poultry production industry. This study assessed the effect of a Met-deficient (MD) diet on chicken liver and kidney health, exploring the associated mechanisms of antioxidant capacity and ileum mucosal immunity. Seventy-two broilers were administered either the control diet (0.46% Met in starter diet, 0.36% Met in grower diet) or the MD diet (0.22% Met in starter diet, 0.24% Met in grower diet). Liver and kidney samples were collected every 14 days for anatomical, histological, and ultrastructural analyses, accompanied by oxidative stress assessment. Meanwhile, T- and B-lymphocyte abundance and essential cytokine gene expression were measured in the ileum, the center of the gut–liver–kidney axis. Signs of kidney and liver injury were observed morphologically in the MD group at 42 days of age. Furthermore, aspartate aminotransferase, alanine aminotransferase, creatinine, and uric acid levels were decreased in the MD group compared with the control group, accompanied by decreased superoxide dismutase activity, increased malondialdehyde content, decreased numbers of T and B lymphocytes, and decreased cytokine expression in the ileum, such as IL-2, IL-6, LITAF, and IFN-γ. These results suggest that MD can induce kidney and liver injury, and the injury pathway might be related to oxidative stress and intestinal immunosuppression.

Supplemental methionine and stocking density affect antioxidant status, fatty acid profiles, and growth performance of broiler chickens

Broilers stocked in high densities may be prone to oxidative and inflammatory insults, resulting in impaired health status, growth performance, and meat quality. This study was to determine if 30% extra supplemental dl-methionine alleviated or prevented those adverse effects of a higher stocking density in broiler chickens. A total of 560 male Cornish Cross cockerels (day old) were divided into four groups: two stocking densities (9 and 12 birds/m2) and two supplementations of methionine (grower: 2.90 or 3.77 g/kg and finisher: 2.60 or 3.38 g/kg). Growth performance was recorded weekly. Blood and tissues were sampled at the end of each period. High stocking density decreased (P < 0.05) body weight and growth performance of growers and (or) finishers. Those differences were partially attenuated by the extra methionine supplementation. The high methionine elevated (P < 0.05) glutathione (GSH) concentration in the thigh at both ages (> 24%). The high stocking density elevated (>28%, P < 0.05) glutathione concentration in the plasma, breast, and thigh of growers, but decreased (P < 0.05) it in the liver of growers and thigh of finishers. Interaction effects (P < 0.05) between dietary methionine and stocking density were found on activities of the antioxidant enzyme glutathione S-transferase in the liver of growers and breast, thigh, and adipose tissue of finishers. The interaction effect was also found on activities of glutathione peroxidase and superoxide dismutase in the thigh of growers. The extra methionine decreased (P < 0.05) hepatic gene expression of heat shock protein 90 (18%) and thigh and breast malondialdehyde concentrations of the finishers (35%). In conclusion, the 30% extra dl-methionine supplementation was able to partially mitigate adverse effects caused by the higher stocking density and to improve the redox status of the broilers.

Growth Performance of Broilers as Influenced by Different Levels and Sources of Methionine Plus Cysteine

Simple Summary

The current work evaluated the utilization of different sources of methionine either from DL-methionine (DL-Met) or L-methionine (L-Met) using different concentrations of dietary methionine plus cystine (Met + Cyst) in broiler chickens. Results showed that a better edible meat yield could be obtained by supplementing Met + Cyst at the rate of 80% of the digestible lysine.

Abstract

The objective of this work was to evaluate the utilization of methionine from DL-methionine (DL-Met) and L-methionine (L-Met) with different levels of dietary methionine plus cystine (Met + Cyst) in broilers. The experimental diets were formulated by using three levels of Met + Cyst, i.e., 74%, 77% and 80% of digestible lysine. Met + Cyst was provided either from DL-Met or L-Met. A total of 450 day-old broilers were divided into six groups (five replicates of 15 birds each) in a 3 × 2 factorial arrangement under completely randomized design. Weight gain (WG), feed intake (FI) and feed conversion ratio (FCR) was determined. At the end of the experiment (35 days), two birds from each replicate were slaughtered to determine carcass characteristics and serum homocysteine. Results indicate that the combined effect of L-Met and DL-Met significantly affected (p < 0.05) the WG in the starter period and FI in the finisher period. Neither source nor level of methionine influenced (p > 0.05) the FI, WG and FCR of broilers during the starter, finisher or overall phase of growth. The interaction between sources and levels of methionine did not influence (p > 0.05) the feed intake, weight gain and FCR during the overall phase of growth. Source of methionine had no (p > 0.05) effect on carcass characteristics. Methionine levels had a significant effect (p < 0.05) on carcass weight, chest weight and thigh weight. The interaction between sources and levels of methionine had a significant (p < 0.05) effect on the liver weight. The sources of methionine had significant (p < 0.05) effects on the liver and heart weight, while methionine levels significantly influenced (p < 0.05) the liver and gizzard weight. Finally, it was concluded that if DL-Met and L-Met are included in feed at a standard level, they are equally effective as a source of methionine for broilers.

Effects of dietary methionine on growth performance, meat quality and oxidative status of breast muscle in fast- and slow-growing broilers

This experiment was conducted to investigate the effects of dietary methionine (Met) on growth performance, carcass traits, meat quality and oxidative status of breast muscle in fast- (Arbor Acres, AA) and slow- (Partridge Shank, PS) growing broilers from 1 to 42 d of age. The broilers were divided into a 2 × 3 factorial design with 6 replicates per treatment. Diets were formulated to contain low (LM, 0.35 and 0.31% during 1 to 21 and 22 to 42 d), adequate (AM, 0.50 and 0.44%) and high (HM, 0.65 and 0.57%) Met, respectively. The main effects showed that the AA broilers had superior (P < 0.05) growth performance and carcass traits compared with those of the PS broilers. The breast muscle of the AA broilers had lower (P < 0.05) drip loss and malondialdehyde (MDA) content but higher (P < 0.05) cooking loss and glutathione peroxidase (GPX) activity than that of the PS broilers. Compared with the LM diets, the AM and HM diets increased (P < 0.05) 42-d BW, ADG, eviscerated yield and breast muscle yield only in the AA broilers. The AA broilers fed the HM diets had higher (P < 0.05) pH but lower (P < 0.05) L*, cooking loss and ether extract content in breast muscle than those fed the LM diets. Compared with the LM diets, the HM diets resulted in strain-dependent changes (P < 0.05) in muscle oxidative status, with total antioxidant capacity (T-AOC) increased in the AA broilers, GPX activity increased and MDA content decreased in the PS broilers, and superoxide dismutase (SOD) activity increased in both strains of broilers. No differences were observed between the AM and HM diets except for T-AOC in breast muscle. In conclusion, the LM treatment negatively affected broiler growth performance, carcass traits, meat quality and oxidative status of breast muscle in a strain-dependent manner, particularly in the AA broilers, whereas the HM treatment had limited effects compared to the AM treatment.

Methionine supplementation of low-protein diet and subsequent feeding of low-energy diet on the performance and blood chemical profile of broiler chickens

The effects were investigated of supplementing methionine (Met) in a low-crude protein diet (Low-CP+Met) during Days 11–24 post-hatch and subsequent feeding with a low-metabolisable energy diet (Low-ME; –0.31 MJ/kg) during Days 25–42 on the productive performance and blood chemistry profile of broiler chickens. The 1600 broiler chicks were divided into four groups and fed as follows: (1) Control diet; (2) Low-CP (Met deficiency) diet during Days 11–24, then re-feeding with conventional diet; (3) Low-CP+Met diet during days 11–24, then re-feeding with conventional diet; and (4) Low-CP+Met+Low-ME diet (Low-CP+Met diet during Days 11–24, then re-feeding with Low-ME diet). During Days 11–24, the growth performance of the Control group was better than the other groups (P < 0.01), although the Low-CP+Met diet improved bodyweight, feed conversion ratio and improved the protein conversion ratio compare to the Low-CP group (P < 0.01). During the re-feeding phase (Days 25–42), reducing the dietary energy resulted in better growth performance and a better protein conversion ratio and energy conversion ratio than in the Control group (P < 0.05). Triglyceride, very low-density lipoprotein, low-density lipoprotein-cholesterol and total cholesterol in serum were higher, and non-esterified fatty acid was lower in the Control group than those of the Low-CP+Met+Low-ME group (P < 0.05). In conclusion, reducing dietary protein with balanced amino acids during the grower period and subsequent feeding with a low-energy diet promoted productive performance, improved protein utilisation and reduced fat accumulation via increasing lipolysis and/or disruption of the triglyceride transportation in broiler chickens.

Effects of different levels of sanguinarine on antioxidant indices, immunological responses, ileal microbial counts and jejunal morphology of laying hens fed diets with different levels of crude protein

This study was carried out to assess the effects of different levels of sanguinarine on antioxidant indices, immunological responses, serum biochemical parameters, ileal microbial counts and jejunal morphology of laying hens fed on diets with different levels of crude protein (CP). A total of 180 laying hens were subjected into nine dietary treatments with four cages of five birds each. Experimental treatments consisted of three levels of CP (85.0, 92.5 and 100% of Hy-Line W36 manual recommendation) and three levels of sanguinarine (0.00, 3.75 and 7.50 mg/kg) as a 3 × 3 factorial arrangement of laying hens which fed during a 70-day feeding trial. The in vitro study showed that sanguinarine exhibited sevenfold and threefold decreased antioxidant activities to inhibit 2-2-diphenyl-1-picric hydrazyl free radical as well as ferric ion reducing rather than butylated hydroxyl toluene. Although using the decremental levels of CP caused the increase in heterophil-to-lymphocyte ratio (p < 0.01), dietary administration of sanguinarine could suppress the serum cholesterol and malondialdehyde concentrations as well as heterophil-to-lymphocyte ratio (p < 0.05). Additionally, decreasing CP content resulted in the decreased percentage of albumin (p < 0.05); however, it had no negative effects on humoral immunity. Nonetheless, feeding of at least 3.75 mg/kg sanguinarine led to the remarkable increases in serum gamma globulin concentration (p < 0.01) and secondary (p < 0.05) antibody titres against sheep red blood cells. Moreover, a decline in dietary CP content led to higher villi height and crypt depth (p < 0.05; p < 0.001) and consequently decreased villi height-to-crypt depth ratio (p < 0.001) than the optimum level (100% CP). In spite of the effects of sanguinarine on the suppression of Escherichia coli and Salmonella counts (p < 0.05), it markedly enhanced villi height-to-crypt depth ratio as well as lamina propria lymphatic follicles extent, simultaneously (p < 0.001). Therefore, in spite of the detrimental effects of feeding low-CP diets on lymphocytes and serum albumin percentages, and villi height-to-crypt depth ratio, the administration of incremental levels of sanguinarine could improve cellular and humoral immunity, decrease ileal microbial counts and in turn improve the intestinal health indices in laying hens.

Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response

This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions.During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70% (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.