Comparison of absorption kinetics and utilisation of DL-methionine (DL-Met), Met-Met product (AQUAVI® Met-Met), and protein-bound methionine (PB-Met) by female broiler chickens.

1. Two experiments were conducted to determine the effects of different methionine (Met) sources regarding their absorption kinetics and utilisation in female single-meal-fed broiler chickens.2. A total of 340, one day old female Ross 308 broiler chickens were fed commercial starter and grower diets for 38 d. Birds were then allocated to treatment diets in two experiments as a completely randomised design with four replicates of five chicks per each until 60 d of age. In experiment 1, a 2 × 5 factorial design was used to investigate the effect of two sources (DL-Met and AQUAVI®Met-Met) and five equimolar levels (0.4, 0.8, 1.2, 1.6, and 2 g/kg) in the diet. In experiment 2, different proportions of protein-bound methionine (PB-Met) to DL-Met (0.4:1.6, 0.8:1.2, 1.2:0.8: 1.6:0.4, and 2:0 g/kg) were incorporated into a basal diet deficient in Met. During the experiment, chickens received 90 g of pelleted feed for a time period of 17 ± 2.5 min, once daily.3. The results indicated that chickens fed diets supplemented with DL-Met and Met-Met showed a rapid rise in plasma Met 1 h after feeding, with a sudden drop at 2 h after feeding. In contrast, chickens fed PB-Met substituted diets showed a gradual plasma peak at 1 and 2 h postprandial (P < 0.01). Plasma homocysteine (HCY) content increased to 34.38 and 40.43 µmol/l with DL-Met2.0 and Met-Met2.0 diets, while it decreased to 25.68 µmol/l with PB-Met2.0(P ≤ 0.01). Chickens that received the PB-Met2.0 diet had higher (P ≤ 0.01) protein utilisation (0.54 g/g) and lower excreta nitrogen content (4.04 g/100 g excreta), which demonstrated the benefits of feeding a protein-bound Met source. The efficiency of Met utilisation was 0.69 g/g in chickens fed PB-Met2.0 diet, but only 0.36 and 0.41 g/g in those fed DL-Met2.0 and Met-Met2.0 (P ≤ 0.01).4. The observed utilisation coefficient of DL-Met and Met-Met for single-meal meat-type chickens was lower than expected. The synchronisation of intestinal Met absorption maintained the efficiency of utilisation, which was related to the sources of added Met, with protein-bound Met showing the best utilisation and least excretion.

Arginine, soy isoflavone and hydroxypropylmethylcellulose have protective effects against obesity in broiler breeder hens fed on high-energy diets.

1. The present study was undertaken to determine the effects of arginine, soy isoflavone (ISF) and hydroxypropylmethylcellulose (HPMC) on obesity in broiler breeder hens. 2. A total of 320 Cobb 500 hens, 45 weeks of age, were assigned to 64 floor pens. The experiment was conducted as a completely randomised design in a factorial arrangement (2 × 2 × 2 × 2) with 4 replicates of 5 hens in each pen. Factors included two concentrations of HPMC (0 and 1%), two concentrations of arginine (8.4 and 12 g/kg), two concentrations of ISF (zero and three times more than that present in basal diets) and two contents of energy (11.7 and 14.6 MJ/kg). Performance criteria and blood characteristics of hens were measured during the experimental period. Expression of genes involved in lipid metabolism was determined in the liver at 55 weeks of age. 3. Hens given high-energy diets showed increased BW (body weight), ovary weight and abdominal fat pad and enhanced plasma glucose, triglyceride (TG), cholesterol, haemoglobin, haematocrit and low lymphocyte percentages. The expression of malic enzyme, peroxisome proliferator-activated receptor-α (PPARα), peroxisome proliferator-activated receptor-γ (PPARγ) and inducible nitric oxide (iNOS) increased and sterol regulatory element binding protein-1c (SREBP1c) decreased with increasing energy content of diets. Arginine addition decreased TG, cholesterol and A1-c haemoglobin concentration and increased PPARα, PPARγ and iNOS expression. Inclusion of ISF and HPMC decreased BW, egg weight, plasma TG, cholesterol and increased egg production and also enhanced PPARγ and iNOS expression. Significant interactions were observed between energy concentration and ISF and HPMC on BW. 4. The results of the current study revealed that ISF, HPMC and arginine have beneficial effects on controlling the metabolism of obese broiler breeder hens and using a mix of these products minimises the harmful effects of obesity.