ABSTRACT A total of 360 one-day-old Cobb 500 chicks were randomly distributed in a completely randomized design according to a 3×2 factorial arrangement, consisting of three levels of dietary crude protein (100, 90 and 85% of NRCrecommended levels) and a feed additive (with or without feed additive). A blend of a commercial probiotic and a prebiotic were used as feed additives. Each treatment had four replicates of 15 birds each. Prebiotic and probiotic were added to the starter (days 1 to 21) and finisher (days 22 to 42) diets according to the manufacturer´s recommendations. The findings indicated that significant differences were not observed between 100 and 90% NRC for broiler performance (body weight, body weight gain, feed intake and feed conversion ratio) throughout the experiment, while the birds fed the diets containing 85% NRC had poorer performance than those fed 100% (p<0.05). Feed additives had no significant effect on broilers performance. There was no significant interaction between protein level and feed additive for performance. Dietary inclusion of feed additives had no significant effect on cecal lactobacillus and Escherichia coli counts at 21 days of age, while, at 42 days of age, feed additive increased lactobacillus and decreased the counts of Escherichia coli (p< 0.05). In conclusion, according to the findings of the current experiment, dietary crude protein could be reduced by 10%, without negative effect on broiler performance. Supplementation with feed additives had no significant effect on broiler performance, but beneficially influenced cecal bacteria counts at 42 days of age.

This study was conducted to investigate the potential for replacing corn with oak acorn (OA), a tannin-rich feedstuff, and the possible role of polyethylene glycol (PEG) in reducing detrimental effects of OA on broilers. A 3 × 2 factorial arrangement of treatments was used with three levels of OA (0, 150, and 200 g/kg diet), with and without 10 g/kg PEG. A total of 528 one-day-old male and female Cobb 500 broiler chicks were randomly assigned to one of six experimental treatments, with four replicates of 22 birds each. OA was included in the starter (days 1-21) and finisher (days 22-42) diets as a replacement for corn, without changing the dietary levels of other ingredients. The results indicated that dietary inclusion of OA, without PEG, significantly reduced bodyweight gain (BWG) overall (days 1-42) and resulted in worse finisher and overall feed conversion ratios (FCR). PEG had no significant effect on the performance of birds fed diets without OA, but improved overall the BWG of birds receiving 150 and 200 g/kg OA as well as finisher and overall the FCR of birds given 150 g/kg OA. Liver and pancreas weights were not significantly influenced by OA level, PEG or their interaction. Feeding with 200 g/kg OA had deleterious effects on some tibia traits. In conclusion, a significant interaction between OA level and PEG indicates that PEG has the potential to reduce the adverse effects of OA, leading to improved performance. Thus, up to 150 g/kg OA could be included in PEG-supplemented diets, without adverse effects on performance or the tibia traits of broilers.

An experiment was conducted to evaluate the effects of dietary nutrients (protein, methionine, and choline) manipulation on the performance and tibia characteristics of broilers fed diets containing 15% oak acorn. A completely randomized design with five treatments and four replicates of 15 chicks each, was used. One group was fed a diet based on corn (without oak acorn) as control and other four groups were fed diets containing oak acorn with one of the following nutrient manipulation: without nutrient manipulation, high level of methionine (100% more than NRC), high level of CP (10% more than NRC), and addition of 0.2% choline. Starter and finisher diets were fed from one to 21 and 22 to 42 d of age, respectively. The results indicated that group fed diet without nutrient manipulation presented higher feed intake and worse feed conversion ratio (p<0.05) compared with the control group throughout the experiment. Elevated levels of methionine, protein, and choline had significant beneficial effects on feed conversion ratio during starter phase. Feeding oak acorn negatively influenced tibia bone characteristics (bone ash and strength) both at 21 and 42 d of age, whereas the supplementation with protein, methionine and choline prevented those negative effects. In conclusion, dietary inclusion of 15% oak acorn had negative effects on broiler performance and tibia characteristics. Detrimental effects of oak acorn, particularly on tibia bone, were reduced or prevented by increasing the dietary levels of choline, methionine, and protein.

In order to investigate the effects of the dietary supplementation of organic acids, prebiotics and probiotics on broiler chickens, a total of 288 day-old male Cobb chicks were allocated in a completely randomized design according to a 2 x 4 factorial, consisting of two levels of crude protein (recommended or low (85% of recommended)) and a four feed-additive programme. The basal diet without any feed additive served as control and one of the following additives, organic acids, a prebiotic and a probiotic, were added to the basal diet to form the other treatments. Starter and finisher diets were offered from 1 to 21 d and 22 to 42 d of age, respectively. The birds were reared in an open-sided house system under natural tropical conditions with the same housing and general management practices. Lowering the dietary protein level significantly decreased bird performance throughout the experiment. Additives had no significant effects on body weight, body weight gain and feed intake. Dietary supplementation with the prebiotic resulted in significant improvements in feed efficiency during 22 - 42 d and 1 - 42 d of age. At 21 and 42 d of age birds fed the diets containing the prebiotic had the longest duodenal villi compared to the other treatments. Jejunum villi, and duodenum and jejunum crypt depth were not influenced by additives. At 21 d of age the dietary addition of the prebiotic and organic acids significantly increased the antibody titres against Newcastle disease compared to the control group. It could be concluded that under the condition of the current study, the prebiotic affected performance, small intestinal morphology and immunity of broiler chickens significantly.

Leber's hereditary optic neuropathy (LHON) is a maternally inherited form of retinal ganglion cell degeneration leading to optic atrophy in young adults. Several mutations in different genes can cause LHON (heterogeneity). The ND6 gene is one of the mitochondrial genes that encodes subunit 6 of complex I of the respiratory chain. This gene is a hot spot gene. Fourteen Persian LHON patients were analyzed with single-strand conformational polymorphism and DNA sequencing techniques. None of these patients had four primary mutations, G3460A, G11788A, T14484C, and G14459A, related to this disease. We identified twelve nucleotide substitutions, G13702C, T13879C, T14110C, C14167T, G14199T, A14233G, G14272C, A14290G, G14365C, G14368C, T14766C, and T14798C. Eleven of twelve nucleotide substitutions had already been reported as polymorphism. One of the nucleotide substitutions (A14290G) has not been reported. The A14290G nucleotide substitution does not change its amino acid (glutamic acid). We looked for base conservation using DNA star software (MEGALIGN program) as a criterion for pathogenic or nonpathogenic nucleotide substitution in A14290G. The results of ND6 gene alignment in humans and in other species (mouse, cow, elegans worm, and Neurospora crassa mold) revealed that the 14290th base was not conserved. Fifty normal controls were also investigated for this polymorphism in the Iranian population and two had A14290G polymorphism (4%). This study provides evidence that the mtDNA A14290G allele is a new nonpathogenic polymorphism. We suggest follow-up studies regarding this polymorphism in different populations.