Chimpanzee reservoirs of pandemic and nonpandemic HIV-1     

Keele BF  Van Heuverswyn F  Li Y  Bailes E  Takehisa J  Santiago ML  Bibollet-Ruche F  Chen Y  Wain LV  Liegeois F  Loul S  Ngole EM  Bienvenue Y  Delaporte E  Brookfield JF  Sharp PM  Shaw GM  Peeters M  Hahn BH 《Science (New York, N.Y.)》2006,313(5786):523-526

Human immunodeficiency virus type 1 (HIV-1), the cause of human acquired immunodeficiency syndrome (AIDS), is a zoonotic infection of staggering proportions and social impact. Yet uncertainty persists regarding its natural reservoir. The virus most closely related to HIV-1 is a simian immunodeficiency virus (SIV) thus far identified only in captive members of the chimpanzee subspecies Pan troglodytes troglodytes. Here we report the detection of SIVcpz antibodies and nucleic acids in fecal samples from wild-living P. t. troglodytes apes in southern Cameroon, where prevalence rates in some communities reached 29 to 35%. By sequence analysis of endemic SIVcpz strains, we could trace the origins of pandemic (group M) and nonpandemic (group N) HIV-1 to distinct, geographically isolated chimpanzee communities. These findings establish P. t. troglodytes as a natural reservoir of HIV-1.  相似文献   

Apparent Digestibility of Gross Nutrients from Feedstuffs in Extruded Feeds for Rainbow Trout,Oncorhynchus mykiss     

T. Gibson Gaylord  Frederic T. Barrows  Steven D. Rawles 《Journal of the World Aquaculture Society》2008,39(6):827-834

Abstract.— The current experiment was performed to determine apparent protein and energy digestibility coefficients of feed ingredients by the fecal stripping technique using extruded diets. The ingredients tested included five fish meals, three terrestrial animal by‐products, five plant protein concentrates, four plant meals, and seven low‐protein plant ingredients. Protein digestibility differed among fish meals and ranged from 90% for fair and average quality menhaden meal to 97% for anchovy meal. Protein apparent digestibility coefficients (ADCs) in plant concentrates ranged from a low of 89% for rice protein concentrate to a high of 100% for wheat gluten meal. Apparent protein digestibility was lower in plant meals than fish meals with a low of 70% for flaxseed meal to a high of 89% for soybean meal. Low‐protein plant meals had generally lower protein ADC from 64% for rice bran to 85% for whole wheat. A similar pattern for energy ADCs was observed; ADCs ranged from 106% for anchovy meal to 32% for whole wheat. In the current trial, divergent protein and energy ADC values were obtained most notably in ingredients known to be high in fiber or have very high starch content. The comparability of ingredients/diets processed by cold pelleting or extrusion thus appears questionable at this juncture.  相似文献   

Taurine Supplementation of All-plant Protein Diets for Rainbow Trout (Oncorhynchus mykiss)     

T. Gibson  Gaylord  April M.  Teague Frederic T.  Barrows 《Journal of the World Aquaculture Society》2006,37(4):509-517

Abstract.— Taurine has been demonstrated to be conditionally indispensable for several carnivorous fish species. Current trends in trout production include decreasing levels of fish-meal content in feeds, along with faster growing strains of fish. Taurine may be a limiting nutrient in support of elevated planes of growth for rainbow trout. A 9-wk feeding trial was conducted using a factorial treatment design with protein source (fish meal or plant) and taurine supplementation (four levels) as the main effects. The fish-meal diet series included 23% herring meal and contained 1.76% total sulfur amino acids (TSAA). The plant diet series did not contain any animal proteins and substituted protein from soy protein concentrate in place of the herring-meal protein and contained 1.5% TSAA. Taurine was supplemented at 0, 5, 10, and 15 g/kg dry diet to each of the diets in the plant series and the fish-meal series of diets. All diets were formulated to contain 43.8% crude protein and 20% lipid with an estimated physiological fuel value of 4.2 kcal/g. Fifteen fish were stocked in each of 24 tanks with a mean initial weight of approximately 26.8 g per fish. The unsupplemented fish-meal diet contained 2 g/kg taurine, and the unsupplemented plant diet had taurine levels below the detection limit of 0.1 g/kg diet. Taurine supplementation improved growth, feed conversion ratios, protein retention efficiencies, and energy retention efficiencies of fish fed the plant protein diets. No effects of taurine supplementation were observed for these response factors in fish fed the fish-meal series diets. This study demonstrates that taurine supplementation may be necessary for rainbow trout fed plant-protein-based feeds.  相似文献