Threonine in broiler diets: an updated review

Growth performance, liver and kidney functions, blood hormonal profile, and economic efficiency of broilers fed different levels of threonine supplementation during feed restriction

The objective of the existing investigation was to determine the effect of dietary inclusion of threonine amino acid at different levels during feed restriction on growth indices, liver and kidney function parameters, and some hormonal profiles along with economic indicators in broiler chickens. A total of 1,600 from 2 different breeds (800 Ross 308 and 800 Indian River) at 21-day-old age were incorporated. Chicks were randomly assigned into 2 main groups, control and feed-restricted (8 h/d), during the fourth week of age. Each main group was subdivided into 4 groups. The first group was fed a basal diet without adding extra threonine (100%), the second, third, and fourth groups were fed a basal diet with extra threonine levels of 110, 120, and 130%, respectively. Each subgroup consisted of 10 replicates of 10 birds. We noticed that the dietary inclusion of threonine at extra levels in the basal diets significantly enhanced final body weight, body weight gain, and better feed conversion ratio. This was mainly due to the enhanced levels of growth hormone (GH), insulin-like growth factor (IGF1), triiodothyronine (T3), and thyroxine (T4). Moreover, the lowest feed cost per kilogram body weight gain and improved return parameters were reported in control and feed-restricted birds fed higher levels of threonine than other groups. Also, a significant increase in alanine aminotransferase (ALT), aspartate aminotransferase (AST), and urea levels was observed in feed-restricted birds supplemented with 120 and 130% levels of threonine. Hence, we recommend supplementing threonine at levels of 120 and 130% in the diet of broilers to promote growth and profitability.

Multi-country metabolic signature discovery for chicken health classification

INTRODUCTION

To decrease antibiotic resistance, their use as growth promoters in the agricultural sector has been largely abandoned. This may lead to decreased health due to infectious disease or microbiome changes leading to gut inflammation.

OBJECTIVES

We aimed to generate a m/z signature classifying chicken health in blood, and obtain biological insights from the resulting m/z signature.

METHODS

We used direct infusion mass-spectrometry to determine a machine-learned metabolomics signature that classifies chicken health from a blood sample. We then challenged the resulting models by investigating the classification capability of the signature on novel data obtained at poultry houses in previously unseen countries using a Leave-One-Country-Out (LOCO) cross-validation strategy. Additionally, we optimised the number of mass/charge (m/z) values required to maximise the classification capability of Random Forest models, by developing a novel ranking system based on combined univariate t-test and fold-change analyses and building models based on this ranking through forward and reverse feature selection.

RESULTS

The multi-country and LOCO models could classify chicken health. Both resulting 25-m/z and 3784-m/z signatures reliably classified chicken health in multiple countries. Through mummichog enrichment analysis on the large m/z signature, we found changes in amino acid metabolism, including branched chain amino acids and polyamines.

CONCLUSION

We reliably classified chicken health from blood, independent of genetic-, farm-, feed- and country-specific confounding factors. The 25-m/z signature can be used to aid development of a per-metabolite panel. The extended 3784-m/z version can be used to gain a deeper understanding of the metabolic causes and consequences of low chicken health. Together, they may facilitate future treatment, prevention and intervention.

Evaluation of Rosmarinic Acid on Broiler Growth Performance, Serum Biochemistry, Liver Antioxidant Activity, and Muscle Tissue Composition

The aim of the present study was to investigate the effects of dietary supplementation with different doses of rosmarinic acid (RA) on the growth performance, serum biochemical indices, liver antioxidant activity, and muscle nutritional component of broiler chickens during 1-20 days of age. A total of 1000 1-day-old Cobb 500 white-feathered broilers were divided into five groups. Each group included four replicates and 50 birds per replicate. The control group was the basic fodder group fed with a basal diet. The experimental groups included four levels of RA (100, 200, 300, and 400 mg/kg RA added to the basal diet, respectively). The results showed that a quadratic increase in final body weight (BW) and average daily gain (ADG) and a quadratic decrease in the feed/gain (F/G) ratio were observed with increasing dietary RA levels. At 200 mg/kg RA supplementation, growth performance was significantly improved. Moreover, under this RA treatment, the highest levels of total protein and globulin were detected in the serum, the activities of total superoxide dismutase and catalase in the liver of broilers were significantly increased, and the malondialdehyde content was significantly decreased, indicating a higher antioxidant capacity of the liver when 200 mg/kg RA was added to the basal diet. The flavor of the muscle meat was improved by dietary supplementation with 200 mg/kg RA. Therefore, adding 200 mg/kg of RA to the diet could significantly improve the growth performance of broilers, improve liver antioxidant capacity, and improve muscle quality, etc. The addition of RA to broiler feed as a natural antioxidant has great prospects.

Standardized ileal amino acid digestibility of plant-based feedstuffs and phytase supplementation in broiler chicken diets

ABSTRACT The objective was to determine the standardized ileal amino acid digestibility (SIAAD) in soybean meal (SBM), corn + SBM, wheat + SBM and a protein free diet (PFD) associated with phytase. A total of 672 Cobb 500 (493±10g) male chicks were distributed in a completely randomized design with twelve treatments (PFD, PFD + SBM, PFD + corn + SBM and PFD + wheat + SBM, supplemented with 0, 500 and 1000 FTU), eight replicates and seven birds per cage from 14 to 23 days. Phytase supplementation at 500 FTU increased the SIAAD of methionine in SBM (P<0.05) and threonine in corn + SBM (P<0.05). There was no significant effect (P>0.05) for the SIAAD of methionine, arginine and histidine in wheat + SBM as the phytase supplementation. However, the SIAAD of lysine, threonine, isoleucine, phenylalanine, valine, cystine, alanine, aspartic acid, glutamic acid, glycine, serine and tyrosine differed (P<0.05). In general, the SIAAD for SBM, corn + SBM and wheat + SBM are 90.32, 88.65 and 83.97% (0 FTU); 91.31, 88.81 and 88.36% (500 FTU); and 91.36, 87.09 and 87.87% (1000 FTU). In conclusion, the efficacy of phytase for improve the SIAAD vary according to the feedstuff and level of supplementation.

Growth performance and small intestinal morphology of native chickens after feed supplementation with tryptophan and threonine during the starter phase

Background and Aim:

The amino acid content of feed can affect growth performance of poultry during the first 6 weeks of life or the starter phase. Unlike for broiler and layer chickens, there is no information concerning standard requirements for tryptophan and threonine during the starter phase. This study aimed to determine the amount of threonine and tryptophan that should be supplemented in chicken feed to maximize growth performance and small intestinal morphology of native chickens during the starter phase.

Materials and Methods:

A total of 128 day-old native chickens were divided into four treatment groups with four replications based on a completely randomized design. The treatment diets were as follows: T₀ (control feed); T₁ (T₀+0.10% L-tryptophan+0.35% L-threonine); T₂ (T₀+0.17% L-tryptophan+0.68% L-threonine); and T₃ (T₀+0.25% L-tryptophan+1.00% L-threonine).

Results:

The feed intake was highest for the T₂ and T₃ groups (123.06 and 124.18 g/bird/week, respectively). The T₃ group had the highest body weight gain (49.35 g/bird/week) and carcass weight (201.44 g/bird) relative to the other groups, while the T₂ and T₃ groups showed similar, significant (p<0.05) increases in feed conversion ratio (2.57 and 2.51, respectively) and carcass percentage (60.88 and 60.99%/bird, respectively) compared to the other groups. This study showed villi height, crypt depth, and villi width of duodenum, the highest jejunum and ileum of T3 (1109.00±27.26, 1325.50±75.00, 1229.50±101.68, 225.50±17.52, 236.00±24.81, 219.75±17.25, 192.25±14.41, 191.75±4.79, and 184.75±6.40, respectively) compare to other treatment.

Conclusion:

These results indicate that supplementation of feed with 0.17% L-tryptophan and 0.68% L-threonine positively affected the growth performance and small intestinal morphology of native chickens during the starter phase.

Interactive effects of threonine levels and protein source on growth performance and carcass traits, gut morphology, ileal digestibility of protein and amino acids, and immunity in broilers

An experiment was executed to test the hypothesis that supplementation of dietary threonine (d-Thr), above NRC recommendation to diets containing poorly digestible protein source (PS) may compensate its detrimental effects on overall performance of broilers. In total, nine hundred 1-day-old mixed sex broilers (Ross-308) were randomly distributed over 6 (2 × 3) experimental diets comprising 5 replicates of 30 broilers each for 35 d. The experimental diets contain either soybean meal (SBM) or canola meal (CM) with 3 levels (100, 110, and 120% of NRC recommendation) of d-Thr. During the course of the trial (0 to 35 D), interactions (P < 0.05) between PS and d-Thr were observed for feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), carcass, and gut health parameters. The broilers fed recommended level (100%) of d-Thr had 7 and 5% poorer FCR compared with those fed diets with 110 and 120% d-Thr, respectively. For villus height (VH), an interaction (P = 0.007) was found between PS and d-Thr level. Broilers consuming SBM diets had 22% longer villi, 10% deeper crypts, and 30% greater VH to crypt depth ratio (VCR) compared to those fed CM. The broilers fed 110% d-Thr diets had 9% lower crypt depth (CD) and 15% greater VCR compared with those fed diets containing NRC recommended levels. CM resulted in 9% lower protein digestibility with lower (P < 0.05) of some AA, whereas it was improved by 7% in broilers fed 120% d-Thr supplemented diets. The bursa and spleen weights were positively affected (P < 0.001) by PS. Threonine supplementation (10%) resulted in 25% greater thymus, 18% heavier bursa, and 30% greater infectious bursal disease titer. In conclusion, supplementation of d-Thr, above NRC recommendation, resulted in a better growth performance and carcass traits, improved ileal digestibility of protein and amino acids, better gut health, and immunity in broilers.

Estimates for digestible threonine: lysine for 21 - 35-day-old female meat-type quails

ABSTRACT Two assays were performed to estimate digestible threonine-lysine (Threo-Lys) ratio for female meat-type quails between 21 and 28 days old and between 28 and 35 days old. Experimental design was totally randomized. The first assay comprised 440 quails distributed into 5 treatments, 8 replications and 11 fowls per cage. The second assay comprised 280 quails distributed into 5 treatments, 8 replications and 7 fowls per cage. Five digestible Threo: Lys ratios were evaluated (0.66, 0.71, 0.76, 0.81 and 0.86). Performance, carcass and cut yield, chemical composition of carcass and nitrogen balance were evaluated. There was an improvement (P<0.05) in feed conversion and increase in feed intake due to ratios of digestible Threo: Lys between 21 and 28 and between 29 and 35 days olds, respectively. At 35 days old, there was a better (P<0.05) carcass yield and a negative nitrogen balance for Threo: Lys analyzed. A ratio of 0.86 may be recommended for digestible Threo: Lys as the best for feed conversion and carcass yield for female meat-type quails between 21 and 28 and between 28 and 35 days.

Effects of Dietary Threonine Levels on Intestinal Immunity and Antioxidant Capacity Based on Cecal Metabolites and Transcription Sequencing of Broiler

Simple Summary

Threonine (Thr), an indispensable amino acid for animals and the third limiting amino acid of broilers, plays a vital role in the synthesis of gut mucosal proteins, which also has better effects on growth performance, biochemical indexes, antioxidant function, and gut morphology, as well as acting as a nutrient immunomodulator that affects the intestinal barrier function of broilers. However, it is not clear how it works in depth. The objective of the current study was to investigate the mechanism of effects of different dietary threonine levels on the antioxidant and immune capacity of broilers. Our findings suggest that a Thr level of 125% NRC (Nutrient Requirements of Poultry, 1994) recommendations had better effects on antioxidant and immune capacity, including resisting viruses and decreasing the abnormal proliferation of cells. As well as this, it also had better effects on maintaining the homeostasis of the body.

Abstract

This study aimed to determine the effects of different dietary threonine levels on the antioxidant and immune capacity and the immunity of broilers. A total of 432 one-day-old Arbor Acres (AA) broilers were randomly assigned to 4 groups, each with 6 replicates of 18 broilers. The amount of dietary threonine in the four treatments reached 85%, 100%, 125%, and 150% of the NRC (Nutrient Requirements of Poultry, 1994) recommendation for broilers (marked as THR85, THR100, THR125, and THR150). After 42 days of feeding, the cecum contents and jejunum mucosa were collected for metabolic analysis and transcriptional sequencing. The results indicated that under the condition of regular and non-disease growth of broilers, compared with that of the THR85 and THR150 groups, the metabolic profile of the THR125 group was significantly higher than that of the standard requirement group. Compared with the THR100 group, the THR125 group improved antioxidant ability and immunity of broilers and enhanced the ability of resisting viruses. The antioxidant gene CAT was upregulated. PLCD1, which is involved in immune signal transduction and plays a role in cancer suppression, was also upregulated. Carcinogenic or indirect genes PKM2, ACY1, HK2, and TBXA2 were down-regulated. The genes GPT2, glude2, and G6PC, which played an important role in maintaining homeostasis, were up-regulated. Therefore, the present study suggests that 125% of the NRC recommendations for Thr level had better effects on antioxidant and immune capacity, as well as maintaining the homeostasis of the body.