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

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.     

Analysis of ochratoxin A in foods consumed by inhabitants from an area with balkan endemic nephropathy: a 1 month follow-up study

In the 1950s, a series of publications from Bulgaria, Yugoslavia, and Romania locally described a kidney disease called Balkan Endemic Nephropathy (BEN). In Bulgaria, the exposure of populations to ochratoxin A (OTA) was supported by analysis of individual food items demonstrating a higher prevalence and higher levels of OTA in food from the high-incidence areas of BEN. In this work, food consumption from a series of individuals from two villages of the BEN area during 1 month was followed using the duplicate diet method. Meals consumed by volunteers from both villages showed uneven OTA contents, spreading from below the limit of quantification (<0.07 microg/kg) to 2.6 microg/kg. The average weekly intake of OTA varies from 1.86 to 92.7 ng/kg of body weight. Some of these levels approach the provisional tolerable weekly intake (PTWI) established by the JECFA at 100 ng/kg of body weight. These results confirm previous studies performed in the same area and demonstrate the high exposure of this population to OTA, thus strengthening the hypothesis of the involvement of this mycotoxin in BEN etiology.     

Infectious bronchitis virus in testicles and venereal transmission

Even though males represent only 8%-12% of the birds of a breeder flock, their role in infectious bronchitis virus (IBV) dissemination is largely unknown. We first assessed the effect of IBV replication in the chicken testes. Ten-week-old males were inoculated with Arkansas (Ark) or Massachusetts (Mass) IBV virulent strains. Seven days postinoculation (DPI) IBV RNA was detected in testicles of 100% of M41- and in 96% of Ark-infected males. Marginal nonsynonymous variation was detected in spike (S) gene of the predominant population of IBV replicating in the testes compared to the S gene of the predominant population of viruses prior to inoculation. IBV M41 and Ark were detected in spermatogonia and Sertoli cells of testicles of infected roosters by immunofluorescence, without evident histopathological changes. We next assessed venereal transmission of IBV by artificially inseminating 54-wk-old hens either with semen from IBV-infected roosters or with IBV suspended in na?ve semen. IBV RNA was detected in the trachea of all hens inseminated with IBV-spiked semen and in 50% of hens inseminated with semen from IBV-infected males. The egg internal and external quality was negatively affected in hens inseminated with semen containing IBV. These results provide experimental evidence for IBV venereal transmission.     

Water loss regulation in mature Hevea brasiliensis: effects of intermittent drought in the rainy season and hydraulic regulation

Effects of soil and atmospheric drought on whole-tree transpiration (E(T)), leaf water potential (Ψ(L)) and whole-tree hydraulic conductance (K(T)) were investigated in mature rubber trees (Hevea brasiliensis, clone RRIM 600) during the full canopy stage in the rainy season in a drought-prone area of northeast Thailand. Under well-watered soil conditions, transpiration was tightly regulated in response to high evaporative demand, i.e., above reference evapotranspiration (ET(0)) ~2.2 mm day(-1) or maximum vapor pressure deficit ~1.8 kPa. When the trees experienced intermittent soil drought E(T) decreased sharply when relative extractable water in the top soil was?相似文献   

Identification and functional characterization of ApisOr23 in pea aphid Acyrthosiphon pisum

Pea aphid,Acyrthosiphon pisum,is a serious pest of many different leguminous plants,and it mainly relies on its odorant receptors(Ors) to discriminate among host species.However,less is known about the role that Ors play in the host plant location.In this study,we identified a novel conserved odorant receptor clade by phylogenetic analysis,and conducted the functional analysis of ApisOr23 in A.pisum.The results showed that the homologous Ors from A.pisum,Aphis glycines and Aphis gossypii share 9...     

Examination of the Effects of Dietary Protein and Lipid Levels on Growth and Stress Tolerance of Juvenile Tilapia,Oreochromis niloticus

Tilapia is the second most consumed farmed fish after carp and the most widely grown farmed fish. However, significant price increases in ingredients in recent years threaten profitability of the industry because dietary costs are approximately 60% of production costs. Therefore, the objective of this study was to optimize dietary protein and lipid levels of juvenile tilapia cultured in high‐intensity recirculating‐water system and assess dietary effects on stress tolerance. To achieve this objective, a factorial treatment design with diets formulated to contain three levels of dietary protein (28, 32, and 36%) and three levels of dietary lipid (3, 6, and 9%) was employed. Juvenile tilapia (34.5 ± 0.4 g initial weight) were randomly assigned to each of 24 tanks and fed one of the nine diets, three feedings per day to apparent satiation, 6 d/wk for 12 wk. Fish were weighed and counted every 3 wk and feed consumed recorded weekly. Tilapia weight gain, feed conversion, feed intake, and proximate composition were significantly affected by diet. Following the feeding trial, tilapia were subjected to a 24 h simulated live haul where fish were stocked into a static water system at 0.24 kg/L of water. Glucose, lactate, and cortisol measurements were taken at time 0, 24, and 72 h after fish were placed into hauling containers. There was significant effects (P < 0.05) of crude lipid and crude protein on blood chemistry parameters. These data indicate that practical diet formulations can be improved to enhance growth rates, production of tilapia, and stress response during live hauls.     

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

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.     

Performance of Post-juvenile Rainbow Trout Oncorhynchus mykiss Fed Diets Manufactured by Different Processing Techniques

Four different methods of pelleting—extruded (EXT), steam pelleted (STM), using a Universal Pellet Cooker (UPC), and expanded (EXP)—were performed on subsamples of a single batch of mash to determine the effects on feed pellet characteristics, in vivo feed digestibility, and performance of rainbow trout Oncorhynchus mykiss fed the diets for 16 wk. Results indicated that the STM feed was the most (851 g/L) and UPC feed the least (672 g/L) dense, and that UPC feed had the highest % float (8.3%) and, of the pellets that sank, the fastest sink rate (15.1 cm/sec). While some differences occurred among pelleted diets in loss of dry matter (% dry loss) after incubation in a water bath for up to 10 min, the overall % dry loss was only approximately 1–2%. The method of pelleting did not affect fish weight gain, feed conversion ratio, or specific growth rate. Measurement of the apparent digestibility coefficient of dry matter of the test diets using Cr₂O₃ as the marker ranged from 71–89%. While it appeared that the method of pelleting can affect feed characteristics and the amount of feed offered to the fish, fish performance was not affected.     

Biological characteristics of chicken anemia virus regenerated from clinical specimen by PCR

Our previous genetic characterization of chicken anemia virus (CAV) in commercial broiler chickens in Alabama revealed a previously undetected polymorphism: a glutamine codon at VP1 position 22, in 7 of the 14 sequences. The novel glutamine codon was always found in association with a VP1 "hypervariable region" identical to CAV field isolates that replicate poorly in culture. The complete genome of CAV73, representative of the sequences with the novel polymorphism, was generated from cloned polymerase chain reaction (PCR) fragments amplified directly from naturally infected tissues. CAV73 had been detected in 31-day-old broilers submitted for examination for reasons unrelated to anemia. After electroporation of the cloned genomes into MDCC-CU147 lymphoblastoid cells, the regenerated CAV caused the culture to fail within 9 days, and the medium contained 5 X 10(6) TCID50 CAV/ml. Use of MDCC-CU147 cells was essential, as identical electroporation of MDCC-MSB1 cells failed to generate CAV able to destroy the culture within 8 wk. Regenerated CAV73 produced anemia and severe lymphocytic depletion of the thymus when inoculated into susceptible 3-day-old chickens and was reisolated from these chickens. Furthermore, it replicated in low- and high-passage MDCC-MSB1 cells similarly to a low-passage CAV field isolate that contains a different VP 1 "hypervariable region." The regeneration of CAV from PCR products directly from naturally infected carcasses, as performed in this study, provides a tool for the evaluation of distinct genetic polymorphisms that may be detected in specimens where infective virions are no longer available. Our results also provide some insight into the differential susceptibility of cell lines for low-passage CAV field isolates.