Effects Of Threonine Supplementation Research Articles

Influence of Threonine Supplementation on Antioxidant Enzyme Activities and Haemato-biochemical Parameters of Commercial Layers in Sub-Tropics

A study was conducted to see the effects of threonine supplementation on antioxidant enzyme activities and haemato-biochemical parameters of commercial layers. Sixteen hundred and eighty (1680) BV-300 laying birds of 40 weeks age with an average body weight of 1353±5.86g were allocated in a completely randomized design with five (5) groups of 336 birds in each. Groups were formed according to the dose of supplemented threonine in various rations i.e. NRC specification, BV-300 strain requirement, 110% of BV-300 strain requirement, 120% of BV-300 strain requirement and 130% of BV-300 strain requirement. With the increasing levels of supplemental L-threonine, GSH-Px activity and serum SOD level increased linearly (p=0.005 and p=0.002, respectively). Among hematological parameters, though non-significant, Heterophils/Lymphocyte ratio tended to decrease linearly (p=0.02). The sugar and total protein concentration increased linearly (p<0.001) while albumin and globulin concentration increased linearly and quadratically. There was a linear decrease (p<0.001) in blood cholesterol level. It may be concluded that L-threonine supplementation at 130% of BV-300 recommendation has a better antioxidant function and better haemato-biochemical parameters.

Effects of threonine supplementation on the growth performance, immunity, oxidative status, intestinal integrity, and barrier function of broilers at the early age

The aim of this study was to investigate effects of L-threonine (L-Thr) supplementation on the growth performance, immunity, antioxidant status, and intestinal health of broilers at the early age. One hundred and forty-four 1-day-old male broiler chicks (Arbor Acres Plus) were allocated into 3 treatments with 6 replicates of 8 birds each, and fed a basal diet (analyzed Thr content, 7.87 g/kg) supplemented with 0 (control diet), 1 and 3 g/kg L-Thr for 21 d, respectively. Treatments did not alter growth performance of broilers. Compared with control, 1 g/kg Thr supplementation increased relative weight of spleen (P = 0.013). A higher level of Thr (3 g/kg) increased relative weight of thymus (P = 0.003). The supplementation of 3 g/kg Thr reduced Escherichia coli (P = 0.040) and Salmonella colonies (P = 0.015), whereas increased Lactobacillus colonies (P < 0.001) in the cecal contents. Thr supplementation increased intestinal villus height (P < 0.05), and the ratio of villus height to crypt depth (P < 0.001), and the values for these parameters were intermediate with 1 g/kg Thr. Goblet cell density was increased by Thr supplementation (P < 0.001). The jejunal immunoglobulin G content was increased by the inclusion of Thr (P = 0.002). Broilers fed diet supplemented with 1 g/kg Thr exhibited increased concentrations of jejunal immunoglobulin M (P = 0.037) and secretory immunoglobulin A (P = 0.018). Likewise, 3 g/kg Thr inclusion increased ileal secretory immunoglobulin A content (P = 0.023). The jejunal malondialdehyde accumulation was reduced by Thr inclusion (P = 0.012). A higher level of Thr inclusion also reduced malondialdehyde content in the serum (P = 0.029). The high level of Thr inclusion (3 g/kg) upregulated mucin-2 mRNA expression (P = 0.034), whereas downregulated the mRNA abundances of interferon-γ (P = 0.036) and interleukin-1β (P = 0.031) in the ileum. In conclusion, L-Thr supplementation can improve immunity, antioxidant capacity, and intestinal health of broilers at an early age.

Effects of threonine supplementation on whole-body protein synthesis and plasma metabolites in growing and mature horses

Current equine threonine requirement estimates do not account for probable use of threonine to maintain gut health and mucin synthesis. The objective of this study was to determine if threonine supplementation (+Thr) would increase whole-body protein synthesis (WBPS) in weanling colts (Study 1) and adult mares (Study 2). Both studies used a crossover design, where each of six animals was studied twice while receiving the isonitrogenous diets. The basal diets contained lower threonine levels (Basal) than the threonine (+Thr) supplemented diets. Threonine intakes in mg/kg BW/day were as follows: 79 (Basal) and 162 (+Thr) for Study 1 and 58 (Basal) and 119 (+Thr) for Study 2, in comparison to the NRC estimated requirements of 81 and 33 mg/kg BW/day for weanling and mature horses, respectively.Following 5 days of adaptation, blood samples were taken before and 90 min after the morning concentrate meal. The next day, whole-body phenylalanine kinetics were determined using a 2 h primed, constant infusion of [13C]sodium bicarbonate followed by a 4 h primed, constant infusion of [1-13C]phenylalanine. Most plasma amino acid (AA) concentrations were elevated post-feeding (P < 0.01). Lysine and valine plasma concentrations were lower (P < 0.10), while methionine, threonine, and glycine plasma concentrations were greater (P < 0.10) 90 min post concentrate meal feeding with +Thr in both studies. Phenylalanine flux, intake, oxidation and non-oxidative disposal were similar between treatments (P > 0.05). These findings suggest that supplementation of a single AA can affect the metabolism of several AAs and threonine was not a limiting AA in these diets.

Effects of Threonine Supplementation on the Slope Assay for Protein Quality

Several diets considered to be marginally deficient in threonine were fed to young male rats at protein levels ranging from 3 to 9%. Protein sources included lactalbumin (reference standard), soy protein with added methionine, pea protein with added methionine, rice-casein, and peanut-sesame-fish. Chemical scores and plasma amino acid scores indicated that these diets were limiting in threonine at the 3--4% protein level; increased growth resulted from supplementation with threonine. After threonine supplementation, all protein sources except pea were limiting in lysine. Increased growth at low protein levels with little or no extra growth at high protein levels due to threonine supplementation resulted in decreased slopes in the relative protein value (RPV) assay. Consequently, threonine supplementation apparently decreased RPV values for these samples but the protein efficiency ratio was not affected. It was concluded that the RPV assay underestimates the protein quality of lysine-deficient proteins.

Effect of threonine supplementation on hepatic polysome patterns and protein synthesis of rats fed a threonine-deficient diet

We have investigated changes in hepatic polysomal pattern and protein synthesis in rats fed a threonine-deficient diet for 1 week and the response that occurred subsequent to threonine supplementation. The experiments showed that: 1. 1. The percentage of hepatic ribosomes in free form or small aggregates was elevated in rats fed a threonine-deficient diet. 2. 2. Administration of threonine alone to rats previously fed the deficient diet increased the degree of ribosomal aggregation but administration of tryptophan or other amino acids was without effect. The shift in polyribosomes toward heavier aggregates was accompanied by an increase in [ 14C]leucine incorporation in vivo into liver proteins. 3. 3. The increase in ribosomal aggregation after administration of threonine was only transitory but reaggregation could be initiated by subsequent administration of a mixture of amino acids devoid of threonine. 4. 4. Involvement of corticosteroid hormones in mediating the response induced by threonine was ruled out, since the stimulatory effects could be produced in both intact and adrenalectomized animals. 5. 5. Actinomycin D did not prevent the enhancement of hepatic protein synthesis induced by threonine, nor did it affect the extent of polysome reformation. The responses to threonine administration would thus seem not to require RNA synthesis which suggests that threonine exerts its effect through a cytoplasmic mechanism.