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1.
Egg production and layer bird mortality data obtained from five different private farms in Zaria within the subhumid zone of Nigeria, over a 6‐year period (1994–1999) were subjected to least squares analysis to determine the effects of age, season and year. It was demonstrated that age had a highly significant influence (P < 0.01) on egg production in that birds falling within the age group 30–39 weeks produced the highest number of eggs (3255 ± 109), while birds over 100 weeks of age produced the lowest number of eggs (1206 ± 412). Similarly, seasonal variation in egg production was also significant (P < 0.05); the highest egg production (2926 ± 90) was obtained during the early dry season, and the lowest (2423 ± 95) during the late wet season. Mortality was generally low (0.0–0.9%) and not significantly different from 20 to 49 weeks of age (P > 0.05). However, from 50 to 100 weeks of age, highly significant differences (P < 0.01) in mortality were observed, with the 90–100 weeks age group recording the highest mortality of 15.7 ± 1.3%. Furthermore, yearly variations in egg production and mortality were highly significant (P < 0.01) with 1999 producing the most eggs (4410 ± 102) and recording the lowest mortality (1.4%). It was concluded that due to the significant seasonal, age and yearly variations, data on egg production and mortality need to be adjusted for these effects to enable unbiased comparison between and within farms. Furthermore, farmers can make adequate feeding preparations commensurate with each season for optimal egg production.  相似文献   
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Soya bean agglutinin (SBA) is a glycoprotein and the main anti‐nutritional component in most soya bean feedstuffs. It is mainly a non‐fibre carbohydrate‐based protein and represents about 10% of soya bean‐based anti‐nutritional effects. In this study, we sought to determine the effects of N‐Acetyl‐D‐galactosamine (GalNAc or D‐GalNAc) on the damage induced by SBA on the membrane permeability and tight junction proteins of piglet intestinal epithelium (IPEC‐J2) cells. The IPEC‐J2 cells were pre‐cultured with 0, 0.125 × 10?4, 0.25 × 10?4, 0.5 × 10?4, 1.0 × 10?4 and 2.0 × 10?4 mmol/L GalNAc at different time period (1, 2, 4 and 8 hr) before being exposed to 0.5 mg/ml SBA for 24 hr. The results indicate that pre‐incubation with GalNAc mitigates the mechanical barrier injury as reflected by a significant increase in trans‐epithelial electric resistance (TEER) value and a decrease in alkaline phosphatase (ALP) activity in cell culture medium pre‐treated with GalNAc before incubation with SBA as both indicate a reduction in cellular membrane permeability. In addition, mRNA levels of the tight junction proteins occludin and claudin‐3 were lower in the SBA‐treated groups without pre‐treatment with GalNAc. The mRNA expression of occludin was reduced by 17.3% and claudin‐3 by 42% (p < 0.01). Moreover, the corresponding protein expression levels were lowered by 17.8% and 43.5% (p < 0.05) respectively. However, in the GalNAc pre‐treated groups, occludin and claudin‐3 mRNAs were reduced by 1.6% (p > 0.05) and 2.7% (p < 0.01), respectively, while the corresponding proteins were reduced by 4.3% and 7.2% (p < 0.05). In conclusion, GalNAc may prevent the effect of SBA on membrane permeability and tight junction proteins on IPEC‐J2s.  相似文献   
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Tropical Animal Health and Production - Two studies at the National Animal Production Research Institute (NAPRI), Zaria, Nigeria, compared Red Sokoto (RS), Sahelian (SG), and West African Dwarf...  相似文献   
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Weeds and diseases can reduce peanut (Arachis hypogaea L.) yield or increase cost of production to maintain acceptable yield. While herbicides and fungicides have limited availability in many areas of Ghana and currently are too expensive for resource-poor farmers, control by these pesticides can have a major positive impact on peanut yield. Field experiments were conducted during the rainy seasons of 2009 and 2010 in northern Ghana to determine the effects of herbicide and hand weeding in combination with fungicides on pest management and peanut yield. Peanut pod yield was often more highly correlated with disease severity and canopy defoliation resulting from early leaf spot (caused by Cercospora arachidicola Hori) and late leaf spot (caused by Cercosporidium personatum (Berk. & M.A. Curtis) Deighton) than weed biomass. In some instances, less disease and canopy defoliation were observed when weeds were not controlled effectively compared with increased weed management through hand weeding or herbicide. Two hand weedings or applying pendimethalin preemergence with one hand weeding in combination with 4 applications of triadimefon and chlorothalonil resulted in the lowest weed density and canopy defoliation and often resulted in the highest peanut yield.  相似文献   
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High copper feed has been widely used as an inexpensive and highly effective feed additive to promote growth performance of pigs. However, long-term feeding of high copper feed may reduce the growth-promoting effects of copper, time-dependent accumulation of copper in animal tissues and organs, and copper toxicity thereby reducing the growth performance of pigs. Due to the widespread effects of high copper supplementation in animals' diets, the benefits and drawbacks of high copper feeding in pigs have been reported in several studies. Meanwhile, few of these studies have systematically described the mechanism by which high copper diets restrain pig growth. Therefore, to address the concerns and give a better understanding of the mechanism of high copper diet in restraining pig growth in different systems, this paper reviews the research progress of long-term supplementation of high copper on the growth of pigs and provides some suggestions and further research directions.  相似文献   
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Plant-parasitic nematodes pose a major threat to crop production in Nigeria. Comprehensive data on yield losses for most cereal crops are not readily available. Research on maize (Zea mays), rice (Oryza sativa), and sorghum (Sorghum bicolor) has shown an 18%–67% reduction in yield linked to the destructiveness of parasitic nematodes, particularly root-knot and root-lesion nematodes. Continuous monoculture and a conservative approach to agriculture increase the incidence and population density of nematodes, leading to higher levels of damage and losses in most cultivated cereal crops. These losses affect the food security of the growing population of Nigeria and many African countries that are heavily dependent on cereals. The accurate identification of nematodes is fundamental for effective management strategies. Nematode taxonomy based on morphology has been difficult due to intraspecific character variations coupled with the limited expertise of indigenous nematologists. Biochemical and molecular marker-based tools and approaches have allowed efficient diagnosis of most nematode species affecting cereal production globally. These approaches have proved useful due to their practicality, rapidness, accuracy, and cost-effectiveness. This review describes the important economic effects of these parasitic nematodes on cereal production and highlights the need for integrative approaches to taxonomy for accurate species identification that will improve nematode diagnosis, thereby contributing to the increase of food production in Nigeria.  相似文献   
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Eleutheroside B (EB) is a phenylpropanoid glycoside with anti‐inflammatory properties, neuroprotective abilities, immunomodulatory effects, antinociceptive effects, and regulation of blood glucose. The aim of this study was to investigate the effects of EB on the barrier function in the intestinal porcine epithelial cells J2 (IPEC‐J2). The IPEC‐J2 cells were inoculated into 96‐well plates at a density of 5 × 103 cells per well for 100% confluence. The cells were cultured in the presence of EB at concentrations of 0, 0.05, 0.10, and 0.20 mg/ml for 48 hr. Then, 0.10 mg/ml was selected as the suitable concentration for the estimation of transepithelial electric resistance (TEER) value, alkaline phosphatase activity, proinflammatory cytokines mRNA expression, tight junction mRNA and protein expression. The results of this study indicated that the supplementation of EB in IPEC‐J2 cells decreased cellular membrane permeability and mRNA expression of proinflammatory cytokines, including interleukin‐6 (IL‐6), interferon‐γ (INF‐γ), and tumour necrosis factor‐α (TNF‐α). The supplementation of EB in IPEC‐J2 cells increased tight junction protein expression and anti‐inflammatory cytokines, interleukin 10 (IL‐10) and transforming growth factor beta (TGF‐β). In addition, the western blotting and real‐time quantitative polymerase chain reaction (RT‐qPCR) results indicated that EB significantly (p < 0.05) increased the mRNA and protein expression of intestinal tight junction proteins, Claudin‐3, Occludin, and Zonula Occludins protein‐1 (ZO‐1). Therefore, dietary supplementation of EB may increase intestinal barrier function, tight junction protein expression, anti‐inflammatory cytokines, and decrease proinflammatory cytokines synthesis in IPEC‐J2 cells.  相似文献   
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Hexavalent chromium [Cr(VI)] is highly toxic, teratogenic and carcinogenic to man and other animals. Some bacterial species have the ability to reduce Cr(VI) to a stable speciation state of trivalent chromium [Cr(III)], which is insoluble and comparatively less toxic. Therefore, the reduction of Cr(VI) thus provides potential as a means for environmental bioremediation of Cr(VI) pollution. In the present study bacteria isolated from chromium and diesel contaminated sites were found to have the ability to rapidly reduce highly toxic concentrations of Cr(VI) to Cr(III) when grown in minimal medium supplemented with glucose as the sole carbon source. Partial chromate reductase gene sequences were retrieved after PCR amplification of genomic DNA extracted from three Gram positive isolates which were highly similar (>99% sequence similarity) to chromate reductase genes found in Gram negative bacteria, more specifically those identified from Escherichia coli and Shigella spp. whole-genome studies. The isolated bacteria were putatively identified by 16S rRNA gene sequencing as Arthrobacter aurescens strain MM10, Bacillus atrophaeus strain MM20, and Rhodococcus erythropolis strain MM30.  相似文献   
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