In this study, 332 lactic acid bacteria of broiler gut origin were investigated as putative probiotic candidates. Sixty-two bacteria showed the highest aggregation while showing antibacterial effects against Salmonella Enteritidis, Salmonella Typhimurium, and Escherichia coli O78:K80. Enzymatic activities of the selected bacteria were examined. No lipase activity was detected, but all of them showed almost similar proteolytic activities. However, they had different amylase and phytase activities. Four of the 62 bacterial strains were selected as a result of aggregation and amylase tests. They were chosen for the following attributes: high cell surface hydrophobicity, co-aggregation, and resistance to bile salts and also acidic conditions. Finally, Lactobacillus crispatus was selected as a source of potential probiotic because of its predominant characteristics in comparison to the other isolated strains from the gastrointestinal tract of chickens. This study has provided a good arrangement of rapid methods for screening a high number of bacteria: a series of beneficial tests that are used together for the first time on chickens, and not any other animals.

An experiment was conducted to study the effects of inclusion of a wheat cultivar (high in nonstarch polysaccharides) and xylanase supplementation of the diet on productive performance, pH of the gastrointestinal tract, nutrient retention, and intestinal enzyme activity of Hy-Line W-36 laying hens from 25 to 47 wk of age. The experiment was completely randomized with 8 treatments arranged factorially with 4 levels of wheat (0, 23, 46, and 69%) that corresponded to a dietary arabinoxylan content of 3.0, 3.3, 3.6, and 3.9%, with or without xylanase supplementation. Each treatment was replicated 5 times. For the entire experimental period, egg weight (P < 0.05) and egg mass (P < 0.01) were reduced and the feed conversion ratio was hindered (P < 0.05) with increased levels of wheat in the diet, but ADFI and egg production were not affected. Xylanase supplementation improved egg production (P < 0.05), egg mass (P < 0.01), and the feed conversion ratio (P < 0.01). Diet did not affect egg quality at any age, except for shell thickness at 47 wk that was improved with xylanase supplementation (P < 0.05). Digesta pH of the different organs of the gastrointestinal tract was not affected by wheat inclusion or xylanase supplementation. Ileal viscosity increased (P < 0.001) with wheat inclusion and decreased (P < 0.001) with xylanase supplementation at all ages. Fat digestibility (P < 0.001) decreased with increased levels of wheat but AME(n) content of the diets (P < 0.05) and nitrogen retention were not affected. Wheat inclusion increased (P < 0.001) amylase (33 wk), lipase (33 wk), and aminopeptidase (47 wk) activity in the duodenum as well as lipase activity in the jejunum at 47 wk of age. However, xylanase supplementation did not affect the activity of any of the enzymes studied. It is concluded that most of the negative effects of wheat inclusion in the diet were reduced or even disappeared with xylanase supplementation. Wheat with a high nonstarch polysaccharide content (Pishtaz cultivar) can be used at levels of up to 69% in laying-hen diets without negatively affecting bird performance, provided that feeds are supplemented with xylanase.

A 42-d trial was conducted to investigate the effect of adding a synbiotic supplement to diets containing two different types of fat on performance, blood lipids and fatty acid (FA) composition and oxidative stability of breast and thigh meat in broilers. A total of 800 one-d-old male broiler chickens were randomly assigned into 1 of 8 treatments with 4 replicates of 25 birds per treatment. The experiment consisted of a 4 × 2 factorial arrangement of treatments including 4 concentrations of synbiotic (0, 0.5, 1 or 1.5 g/kg diet) and 2 types of fat [sunflower oil (SO) or canola oil (CO)] at an inclusion rate of 50 g/kg diet. Dietary fat type did not affect body weight gain (BWG) or feed conversion ratio (FCR) during the overall experimental period (0-42 d). However, fat type modified serum lipid profile and FA composition and 2-thiobarbituric acid-reactive substances (TBARS) content in breast and thigh meat. The addition of synbiotic to the diet linearly improved overall BWG and FCR and also decreased serum cholesterol and low-density lipoprotein cholesterol concentrations. The TBARS value in thigh meat after 30 d of storage at 4°C was linearly decreased as the synbiotic inclusion concentrations in the diets increased. Dietary synbiotic also decreased the proportion of monounsaturated fatty acids and increased n-6 polyunsaturated fatty acid (PUFA) concentration in thigh meat, whereas the FA profile of breast meat was not affected by synbiotic supplementation. Moreover, the PUFA/SFA ratio in the breast meat was linearly increased when synbiotic was included in the CO-containing diets. In conclusion, the addition of synbiotic to broiler diets had a positive effect on growth performance, blood lipid profile and meat quality. The results also support the use of synbiotic to increase the capacity of canola oil for enhancing PUFA/SFA ratio of breast meat in broilers.

No abstract

This research was conducted to investigate the effects of single or combined use of probiotic (Primalac), prebiotic (Fermacto) and butyric acid glycerides (Baby C4) compared to salinomycin on resistance against coccidiosis in broiler chickens challenged with Eimeria. One day-old male Ross 308 broiler chicks were divided into 9 cages with 15 birds per each. Birds of different treatments received a regular corn-soybean meal basal diet supplemented with feed additives; none of them in negative control (C − ), salinomycin in positive control (C ＋ ), probiotic in PRO group, prebiotic in PRE group, butyric acid glycerides in BAG group, probiotic＋prebiotic in PRO＋PRE group, probiotic＋ butyric acid glycerides in PRO＋BAG group, prebiotic＋butyric acid glycerides in PRE＋BAG group, and probiotic ＋prebiotic＋butyric acid glycerides in PRO＋PRE＋BAG group. At 28 d of age, 8 birds from each treatment were removed and kept separately in other cages (2 birds/cage) to challenge with Eimeria. These separated chicks were orally challenged with 1×10 5 E. acervulina and 9×10 4 E. tenella. Positive effect (P＜0.05) was observed in the duodenal and cecal lesion scores in any of the supplemented groups when compared to that of the C − . There was no significant difference between all supplemented groups and C ＋ for cecal lesion score. PRO, PRE＋BAG, PRO＋ PRE, PRO＋BAG and PRO＋PRE＋BAG reduced (P＜0.05) oocyst shedding in birds challenged with Eimeria oocysts compared to the C − , and there was no significant difference between PRO＋PRE, PRO＋BAG, PRO＋PRE ＋BAG and C ＋ . These results demonstrate that prebiotic, butyric acid glycerides and especially probiotic or its combination with prebiotic or butyric acid glycerides enhance the resistance of birds and partially protects against coccidiosis. Therefore, it seems some of these supplements, in comparison to salinomycin, can diminish partially the adverse effects of coccidiosis.