نتایج جستجو برای: old birds
تعداد نتایج: 398943 فیلتر نتایج به سال:
A total of 100, day-old broiler chickens were randomly divided into 5 groups and kept under elevated temperature (34-36EC) to see the effect of ascorbic acid and acetylsalicylic acid (Sb-Asper-C, a commercial product) on the feed conversion ratio (FCR), immune status and ratio of weight of bursa, thymus and spleen to body weight. Heat stress increased the FCR but decreased the immune response a...
The immune response of turkeys to live attenuated vaccine for avian pathogenic Escherichia coli (APEC) constructed from O78 strain was evaluated, where ninety-one-day old turkeys were vaccinated twice with 3 weeks intervals. Other thirty turkeys were kept as non-vaccinated control. Birds were challenged against homologous O78 and heterologous O1 and O2 pathogenic strains of E. coli using 107 CF...
Two repeated experiments were conducted to investigate the effects of different stocking densities onbroiler performance, carcass characteristics, litter quality and foot lesionsusing 5224 one day-old Ross 308 broilers. In each experiment, a total of 2612 one day-old broilers were allocated in 16 floor pens at densities of 16, 18, 20 and 22 birds/m2 of floor space in an environmentally controll...
Determining the timing of diversification of modern birds has been difficult. We combined DNA sequences of clock-like genes for most avian families with 130 fossil birds to generate a new time tree for Neornithes and investigated their biogeographic and diversification dynamics. We found that the most recent common ancestor of modern birds inhabited South America around 95 million years ago, bu...
The objective of this research was to investigate the efficacy of dietary inclusion of probiotics Primalac® and Bactocell® and prebiotic Fermacto® on broiler’s performance and immune response, individually or in combination. A total of 540 one-d-old male Ross 308 broiler chicks were allocated into 6 experimental treatments with 6 replicates of 15 birds per replicate from 1 to 42 d of age. The b...
Body mass of Brünnich’s guillemots Uria lomvia breeding at Coats Island, Canada, was measured during incubation and chick-rearing in 1988 /2001. In most years, mass increased during incubation and fell after hatching, leveling off by the time chicks were 18 d old, close to the age at which chicks departed. Mass during incubation increased with age up to about 12 yr, but the mass of birds broodi...
The majority of our knowledge of avian energetics is based on studies of birds from temperate and high latitudes. Using the largest existing sample of wild-caught Old World tropical species, we showed that birds from Southern Vietnam had lower basal metabolic rate (BMR) than temperate species. The strongest dissimilarity between tropical and temperate species was the low scaling exponent in the...
-Fifty Bobwhite quail (Colinus virginianus) were randomly divided into two equal-size coveys at six weeks of age. At 12 weeks the separation (“hoypoo”) call was recorded from birds in both coveys. Duration and frequency characters were measured and subjected to discriminant analysis. This analysis indicated that each covey could be segregated mainly on the difference in duration between the “ho...
Despite the importance of gut microbiota for broiler performance and health little is known about the composition of this ecosystem, its development and response towards bacterial infections. Therefore, the current study was conducted to address the composition and structure of the microbial community in broiler chickens in a longitudinal study from day 1 to day 28 of age in the gut content and...
The aim of this experiment was to assess the effects of using saturated fatty acid (SFA) and some unsaturated fatty acid (UFA) sources in finishing period on performance, fat deposition and blood metabolites of broiler chickens. One hundred and forty four 28-d old male broiler chickens were randomly assigned to 4 treatments and 6 replicates in a completely randomized design. Four isocaloric/iso...
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