Dietary Threonine Supplementation Research Articles

PSXI-23 Effects of Dietary Threonine, Tryptophan, and Glycine Supplementation on Growth Performance and Intestinal Barrier Function in Broiler Chickens Raised Under Multiple Stress Conditions

Abstract The objective of the current study was to compare the effects of dietary threonine, tryptophan, and glycine supplementation on growth performance and intestinal barrier function in broiler chickens raised under multiple stress conditions. All birds were allotted to 1 of 5 treatments with 8 replicates in a completely randomized design. Positive control (PC) treatment was normal condition and other treatments are multiple stress conditions with heat stress and high stocking density. Multiple stress conditions were exposed to a cyclic heat stress condition (30 ± 0.3°C for 10 h/d and 23 ± 0.2°C for 14 h/d). In addition, 10 birds per cage (16.9 birds/m2) were allotted in multiple stress conditions, but 15 birds per cage (25.3 birds/m2) were allotted in normal conditions. Basal diet was fed to broiler chickens in PC (normal condition) and negative control (NC; multiple stress conditions) treatments. Three additional diets were prepared by adding 0.68% threonine (99%), 0.19% tryptophan (99%), or 1.60% glycine (99%) to the basal diet. Four treatment diets such as NC, threonine, tryptophan, and glycine treatments were provided to birds in multiple stress conditions. All experimental diets and water were provided ad libitum for 14 d. The body weight gain (BWG) and feed intake (FI) were recorded at the end of the experiment. The feed efficiency (FE, g/kg) was calculated by dividing BWG with FI after mortality correction for FI. The intestinal barrier function was analyzed by trans-epithelial electrical resistance (TEER) value in a two-channel Ussing chamber system. Statistical analysis was conducted as a completely randomized design by using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC). The replicate was considered an experimental unit. Outlier data were confirmed by the UNIVARIATE procedure of SAS. The LSMEANS procedure was conducted to calculate treatment means. In addition, if the difference was significant, the PDIFF option of SAS was conducted to separate the means. The significance for statistical tests was considered at P < 0.05. Results indicated that all treatments under multiple stress condition (i.e., NC, Thr, Trp, and Gly treatments) caused a significant reduction (P < 0.05) in BW, BWG, FI, and FE as compared with PC treatment (Table 1). Dietary Thr supplementation under multiple stress conditions was similar FE compared with PC treatment (Table 2). Dietary threonine, tryptophan, and glycine supplementation under multiple stress condition induced intermediated values for TEER with dietary threonine supplementation having similar values to PC treatment. In conclusion, dietary supplementation of threonine seems the most effective functional amino acid. In addition, it can be a novel dietary treatment to improve growth performance and gut health in broiler chickens raised under multiple stress condition.

Effect of dietary threonine supplementation on growth performance and diarrhoea in weaned pigs

A large proportion of antibiotics applied in pig production is used to treat diarrhoea around 2 to 7 weeks post-weaning (PW). Nutritional strategies to prevent diarrhoea in this period are needed if the antibiotic consumption is to be lowered, and additional threonine (Thr) may be one of such strategies. The objective of this study was to test the effect of five levels of dietary Thr on faecal score (diarrhoea) and growth performance day 21 to 32 PW under commercial conditions. The study was part of a larger quadratic surface response trial with 25 treatment groups. A total of 7,952 piglets, weaned approximately at 28 days of age (average body weight (BW) 7.2 kg ± 0.1), were randomly assigned to one of 25 treatment groups, from two weeks PW to 30 kg BW in a balanced incomplete block design. The five Thr levels represented 87%, 100%, 112%, 125% and 137% of the Danish recommended level of Thr for pigs in this weight interval. At 30 kg BW, there were no differences (P > 0.10) in average daily feed intake (ADFI) between the five levels of Thr, whereas average daily gain (ADG) and feed conversion ratio (FCR) were both affected by Thr level (P < 0.05). Piglets receiving 87% of the recommended Thr supply had lower ADG (479 vs. 505–509 g/day) and a higher FCR (1.70 vs. 1.64–1.65 g feed/g growth) compared to pigs receiving the four higher Thr levels. The probability of diarrhoea, defined as a faecal score 3 or 4, was unaffected (P > 0.10) by Thr level at day 21 to 32 PW. Across Thr levels, the probability of diarrhoea was high (25.7% and 26.1%) at day 21 and 25 PW, and decreased with 10.9 percent units at day 28 PW (P = 0.01). There was no difference (P = 0.83) in diarrhoea probability between day 28 and 32. In conclusion, increasing the dietary Thr levels to 110%-140% of the Danish recommendation did not reduce the probability of diarrhoea from day 21–32 PW on a commercial pig farm.

Effects of genetic selection and threonine on meat quality in Pekin ducks

The present study was conducted to investigate the effects of genetic selection and threonine levels on meat quality in Pekin ducks. At 15 D of age, 192 lean ducks and 192 fatty ducks were selected and allotted to one of three treatments with 8 replicates with similar BW (8 ducks/cage), respectively. All ducks were fed the experimental diets (0.00, 0.15, and 0.30% added threonine) for 21 D from 15 to 35 D of age. The results showed that fatty ducks had higher (P < 0.001) feed intake, feed/gain ratio, abdominal fat percentage, and sebum percentage and lower (P = 0.001) breast muscle percentage compared with that of lean ducks. The fatty-type and lean-type ducks had similar weight gain and BW. Dietary threonine supplementation improved (P < 0.05) growth performance and increased breast muscle percentage in lean-type ducks, but it did not affect (P > 0.05) those indices in fatty-type ducks. Lean ducks had higher (P < 0.001) hepatic contents of total lipids, triglyceride, cholesterol, and plasma low-density lipoprotein cholesterol concentration, and dietary threonine supplementation decreased (P < 0.05) hepatic total lipid, cholesterol, and triglyceride contents in lean ducks, but it had no influence on hepatic lipids in fatty ducks (P > 0.05). Lean ducks had higher (P < 0.05) concentrations of monounsaturated fatty acid (MUFA), and C18-polyunsaturated fatty acid (PUFA) in the liver, PUFA in the breast muscle, and C18:3n6 and C18:3n3 in plasma and lower C20-PUFA and C22-PUFA in the liver and MUFA in plasma, compared with fatty ducks. Threonine supplementation increased PUFA, N3-PUFA, and n6-PUFA in plasma and hepatic fatty acids profiles in lean ducks (P > 0.05) but had on influence on total MUFA and total PUFA in the liver, breast muscle, and plasma in fatty ducks (P > 0.05). In conclusion, genetic selection toward meat production and threonine supplementation increases meat production and PUFA contents, which would influence eating quality, but it is benefit for human health.

Effects of dietary threonine supplementation on productivity and expression of genes related to protein deposition and amino acid transportation in breeder hens of yellow-feathered chicken and their offspring

ABSTRACTThis study investigated the effects of the dietary threonine (Thr) levels on the performance, offspring traits, embryo amino acid transportation, and protein deposition in breeder hens of yellow-feathered chickens. In total, 720 breeder hens of Lingnan yellow-feathered chickens were randomly assigned to 1 of 6 dietary treatments, with 6 replicates per treatment (20 birds per replicate). The breeder hens were fed either basal diet (Thr = 0.38%) or basal diet supplemented with 0.12, 0.24, 0.36, 0.48, or 0.60% Thr from 197 to 266 D. There was a positive response in terms of the laying rate after adding different levels of Thr to the diet, but no significant effects on the average daily gain, average daily egg weight, feed conversion ratio, average broken eggs, and unqualified egg rate (P > 0.05). However, the eggshell strength and eggshell percentage decreased in a linear manner as the dietary Thr concentration increased (P = 0.05). Dietary supplementation with Thr had significant effects on the expression of mucin 2 (MUC2) in the uterus and zonula occludens protein 1 (ZO-1) in the duodenum of breeders (P < 0.05). In chick embryos at embryonic age 18 D, significant upregulation of poultry target of rapamycin (pTOR) occurred in the liver and breast muscle, as well as threonine dehydrogenase (TDH) in the thigh, and aminopeptidase (ANPEP) (P < 0.05) in the duodenum and ileum due to dietary Thr supplementation, but there were no effects on MUC2 expression in the duodenum and ileum (P > 0.05). The livability of the progeny broilers tended to increase with the dietary Thr concentration (quadratic, P = 0.08). Thus, dietary supplementation with Thr had positive effects on the laying production by breeder hens and offspring performance, and it also regulated the expression levels of genes related to amino acid transportation and protein deposition. The optimal dietary Thr concentration that maximized the laying rate in yellow-feathered chicken breeders aged 197 to 266 D was 0.68% according to quadratic regression analysis.

Dietary threonine supplementation improves hepatic lipid metabolism of Pekin ducks

The present study was conducted to evaluate the regulatory role of threonine (Thr) on hepatic lipid metabolism by determining the effects of dietary Thr concentration on lipid deposition and on genes related to lipid expression in the liver of Pekin duck. In total, 240 1-day-old ducklings were randomly allocated according to the average bodyweight to one of five dietary treatments with six replicate cages of eight birds per cage for each treatment. Birds were fed diets with 0.52%, 0.59%, 0.66%, 0.73% and 0.80% Thr (as-fed basis) from 1 to 21 days of age respectively. The results showed that dietary Thr supplementation increased average daily gain (P &amp;lt; 0.0001), average daily feed intake (P &amp;lt; 0.0001) and abdominal fat percentage (P &amp;lt; 0.04), while it decreased feed to gain ratio (P &amp;lt; 0.0001), the hepatic contents of total lipid (P &amp;lt; 0.003) and triglycerides (P &amp;lt; 0.003) of Pekin ducks. However, dietary Thr supplementation had no influence (P &amp;gt; 0.05) on the concentration of hepatic cholesterol, and plasma amino acids and biochemical parameters of Pekin ducks. Moreover, Thr-unsupplemented control diet upregulated (P &amp;lt; 0.05) hepatic gene expression related to lipid uptake (fatty acid-binding protein, apolipoprotein A4, lipoprotein lipase), fatty acid synthesis (sterol regulatory element-binding protein 1c, malic enzyme), fatty acid β-oxidation (peroxisome proliferator-activated receptor α, fatty acyl– coenzyme A (CoA) oxidase), ketogenesis (hydroxymethylglutaryl–CoA synthase 1, and acetyl–CoA synthetase1), responsive genes to amino acid deficiency (general control non-derepressible 2 (GCN2), GCN1, eukaryotic initiation factor 2α, impact RWD domain protein (IMPACT)), and triglyceride transport (apolipoprotein B) of Pekin ducks. In addition, dietary Thr deficiency had no effect on the expression of stearoyl CoA desaturase, fatty acid synthase, and ATP–citrate lyase in the liver of Pekin ducks. It is suggested that dietary Thr supplementation improved hepatic lipid metabolism of Pekin ducks by regulating lipid synthesis, transport and oxidation.

Effects of dietary threonine supplementation on intestinal barrier function and gut microbiota of laying hens

The effects of supplemental dietary threonine (Thr) on laying performance, expression of intestinal mucin 2 (MUC2) and secretory IgA (sIgA), and intestinal microbiota of laying hens fed a low CP diet were investigated. A total of 240 Lohmann Brown laying hens, 28 wk of age, was allocated to 3 dietary treatments, each of which included 5 replicates of 16 hens. Hens were fed a control diet (16% CP), a low CP diet (14% CP), or a low CP diet supplemented with 0.3% L-Thr for 12 weeks. Chemical analyses of the diets for Thr are 0.49, 0.45, and 0.69%, respectively. Lowering dietary CP impaired egg production and egg mass of laying hens. Dietary Thr supplementation to the low CP diet increased (P <0.05) egg production and egg mass. In addition, ileal sIgA contents and MUC2 and sIgA mRNA expression were increased (P <0.05) by dietary Thr addition. Dietary CP reduction reduced (P <0.05) intestinal bacterial diversity, whereas dietary Thr supplementation to the low CP diet recovered the bacteria diversity and significantly increased the abundance of potential beneficial bacteria. In conclusion, dietary Thr supplementation to a low CP diet could affect intestinal health and hence productivity via regulating intestinal mucin and sIgA expression, and microbial population of laying hens.

Effects of dietary threonine supplementation on immune challenge induced by swine Pseudorabies live vaccine in weaned pigs

The present study was conducted to determine whether dietary threonine supplementation can improve immunity of weaned pigs challenged by swine Pseudorabies live vaccine (SPLV). Thirty crossbred piglets weaned at 21 days of age were randomly assigned to three groups receiving diets containing true ileal digestible threonine (TIDT) at 0.74, 0.89 and 1.11% for 14 days. On day 8, all pigs were injected intramuscularly with SPLV or sterile 0.9% NaCl solution. SPLV injection enhanced serum IgA, IgM, IgG, IFN-γ, IL-1β, TNF-α and IL-10 concentrations (p < 0.05) and stimulated the relative mRNA abundance of Toll-like receptors (TLR3, TLR7 or TLR9) in different tissues (p < 0.05). Under no challenge, increasing dietary TIDT levels enhanced serum IgG (p < 0.05), IgM (p = 0.07) and IFN-γ (p < 0.05) concentration, tended to decrease serum IL-1β, TNF-α and IL-10 concentration, and regulated relative mRNA abundance of TLR3, TLR7 or TLR9 in different tissues (p < 0.05). However, there was a synergistic role for increasing the serum IL-10 concentration between dietary TIDT levels and SPLV injection (p < 0.05). Under SPLV challenge, increasing dietary TIDT levels attenuated the increase of the serum IFN-γ concentration, and the increase of the relative mRNA abundance of TLR3, TLR7 and TLR9 in the different tissues (p < 0.05). These results suggest that an appropriate dietary threonine supplementation could improve the immune status of weaned pigs injected with SPLV by down-regulating the expression of TLR3, TLR7 and TLR9 in tissues, and thus regulating T-helper cytokine secretion.

Dietary Threonine Supplementation for Improving Growth Performance and Edible Carcass Parts in Japanese Quails, Coturnix coturnix Japonica

3 Abstract: The present study was conducted to evaluate the effects of dietary threonine amino acid supplementation on growth performance and carcass characteristics of Japanese quails. Day old, two hundred and seventy quail chicks were divided into six dietary treatment groups comprising 45 birds each, which consisted of 3 subgroups containing 15 birds for each replicate. Experimental diets were prepared and contained 0.81, 0.86, 0.91, 0.96, 1.01 and 1.06 % threonine amino acid, respective to groups 1-6, on fresh matter basis. Birds were fed these experimental diets respective to treatment for 35 days. Total feed intakes and the changes in body weights were determined on weekly basis. At the end of experiment 35-d, birds were killed humanly to determine their edible carcass parts. Results showed that threonine supplementation to the diet did not affect growth performance and edible carcass parts (p>0.05), assuming that birds can make metabolic adaptation to current dietary threonine supplementations.

Effect of Dietary Threonine Supplementation on Tyrosine Toxicity in the Rat

The objective of this study was to determine the effect of threonine supplementation on tyrosine metabolism in rats fed a low protein diet with excess tyrosine. The growth retardation and the development of eye and paw lesions that occur in rats ingesting a basal plus 3% or 5% L-tyrosine diet could be alleviated partially by the addition of 0.5% or 1.0% L-threonine to the diet. An increased blood tyrosine level in rats fed excess tyrosine was also lowered by threonine supplementation. In tyrotoxic conditions, the activities of liver tyrosine transaminase (EC 2.6.1.5) and threonine dehydratase (EC 4.2.9.16) were elevated, but p-hydroxyphenyl pyruvic acid oxidase (EC 1.13.11.27) which is also intimately associated with tyrosine toxicity was found to be inactivated. Furthermore, biosynthesis of ascorbic acid in liver was significantly lowered in this condition. However, addition of L-threonine in the diet, not only could cure the signs developed due to excess tyrosine, but also could affect the levels of enzymes studied.