Emigration of hatchery‐reared Pallid Sturgeon,Scaphirhynchus albus (Forbes and Richardson), through a Missouri River dam

The middle Missouri River (MMR; Fort Randall Dam, SD to Gavins Point Dam, NE‐SD) is stocked with hatchery‐reared pallid sturgeon, Scaphirhynchus albus (Forbes and Richardson), from upper Missouri River broodstock to aid recovery of this federally endangered species. Emigration of these fish through Gavins Point Dam restores genetic connectivity that likely existed pre‐impoundment but could lead to outbreeding depression in the future. Recapture data of hatchery‐reared pallid sturgeon stocked in the MMR were evaluated to improve understanding of pallid sturgeon emigration. From 2004 to 2015, 219 emigrants were caught: 4 stocked at age ≥2 years and 215 stocked at age ≤1 year. Emigration of the 2001‐2007 year classes stocked at age 1 was a consistent phenomenon and appeared higher than emigration of year classes stocked at ages 2–3. Little evidence suggested emigration was associated with an unusually high‐water event in 2011. The annual emigration probability of individuals stocked at age 1 estimated from multi‐state mark–recapture models was 0.05 [95% confidence interval = 0.04–0.06] for fish ages ≥1 year. This study suggests that alterations to stocking practices (e.g. stocking age) may affect emigration rates and, therefore, connectivity among pallid sturgeon populations.     

Effect of feed and feeding in the culture of salmonids on the marine aquatic environment: a synthesis for European aquaculture

While marine aquaculture has grown rapidly, so have concerns regarding the environmental impacts caused by the industry. In particular, increasing discharges of solid and dissolved fish excretions, nutrients and therapeutic chemicals have coincided with greater public awareness of the possibility of environmental damage. This has stimulated a number of criticisms, drawn from a wide spectrum of interests, ranging from the use of natural fish stocks to produce fish meal for aqua feeds to the effects of enhanced nutrient input on the coastal marine environment. The present study reviews available information on the environmental effects of feeding practices in salmonid aquaculture in Europe. Accumulation of waste food and fish faecal material results in changes in the sediment under fish cages, characterized by a low redox potential, high content of organic material and accumulation of nitrogenous and phosphorous compounds. Although significant environmental impacts have been reported in the literature at distances of up to 100 m from the cages, in general such impacts are reported to be localized to within 20–50 m around the cages. For farmed salmon and trout, mass balance models have been developed for nitrogen and phosphorus, indicating that 50% of the nitrogen and 28% of the phosphorus supplied with the food is wasted in dissolved form. The maximum nutrient release can be estimated from the hydrographic conditions in the immediate vicinity of the farm, such as water volume, tidal water exchange and currents. At present production levels, improvements in the feeding efficiency and feed quality of aquafeeds could reduce waste and consequent environmental impacts.     

An autumn profile of growth regulatory hormones in chinook salmon (Oncorhynchus tshawytscha)

We examined trends in the growth regulatory hormones growth hormone (GH) and insulin-like growth factor-I (IGF-I) from August to December in chinook salmon. Fish on 100% (ad libitum) and 64% rations of a low fat high protein diet, and a 64% ration of commercial feed (BioOregon-grower) were sampled twice a month. Fish were kept on simulated natural photoperiod at constant temperature. GH declined in late August and early September, consistent with photoperiodic regulation. No effects of ration or diet composition on GH were found. IGF-I increased to a peak on 4 October 1998 and declined thereafter. High dietary ration and the higher fat commercial diet increased IGF-I. Fish length and IGF-I level were positively correlated. This study shows that a peak in IGF-I may occur in the fall in chinook salmon. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effect of neonatal thymectomy and antilymphocyte globulin on non-specific mitogen stimulation in Holstein-Friesian calves

Nine of seventeen neonatal Holstein-Friesian calves were thymectomized, treated with antilymphocyte globulin, and monitored for immunologic functional ability for 4 to 6 months. The thymus weights for 4 to 10-day-old calves and 4 to 6-month-old calves indicated a continued increase in total weight. This indicated significant thymic involution had not occurred at 4 to 6 months. Following thymectomy a wasting syndrome was not observed although an increased incidence of a lowly virulent virus infection did occur. A significant decrease in circulating lymphocytes was observed.Peripheral blood lymphocytes were stimulated in vitro by non-specific mitogens, phytohemagglutinin, bacterial lipopolysaccharide and pokeweed mitogen using the whole blood culture method. Observations included a greater response to phytohemagglutinin and pokeweed mitogen in summer months and variable age related response to all mitogens. Lipopolysaccharide stimulation results were inconclusive. It was concluded that neonatal thymectomy was not a satisfactory experimental procedure for the production of selective immunosuppression in the bovine species.     

The Role of Estrogens in the Pathogenesis of Canine Hip Dysplasia. Metabolism of Exogenous Estrogens

Abstract— —Urinary estradiol-17β was measured by gas chromatography in each of 22 normal or dysplastic dogs that had received intramuscular injections of estradiol. Measurable quantities of estradiol-17β were not found in urine from these dogs prior to administration of the exogenous hormone. The level of urinary estradiol-17β was lower in normal dogs than in dysplastic dogs after injection of the hormone. Larger quantities of the hormone occurred in the urine of older dogs of dysplastic lineage after estradiol-17 β injection. These results indicate dogs with hereditary hip dysplasia have a lower than normal capacity to metabolize biologically-active estradiol. Résumé— —L'estradiol-17β urinaire a été mésuré par gas-chromatographie dans chaque des 22 chiens normaux ou dysplastiques qui ont roçu des injections intramusculaires d'estradiol. Des quantités mesurables d'estradiol-17β n'ont pas été trouvées dans Purine de ces chiens avant 1'administration de hormone exogéne. Le niveau d'estradiol-17β urinaire était plus bas chez les chiens normaux que chez les chiens dysplastiques, après l'injection de l'hormone. Des quantités plus grandes de hormone ont ete trouvées dans l'urine des chiens plus âgés du groupe dysplastique, après l'injection d'estradiol— 17β. Les résultats indiquent que les chiens avec dysplasie héréditaire de la hanche ont une capacité moindre que la mornale de métaboliser l'estradiol biologiquement active. Zusammenfassung— —Oestradiol-17β im Urin wurde mittels Gas-Chromotagraphie in 22 normalen odcr dysplastischen Hunden gemessen, die intramuskulaere Injektionen von Oestradiol erhalten hatten. Messbare Mengen von Oestradiol-17β wurden im Urin dieser Hundc vor der Verabreichung des exogenen Hormons nicht gefunden. Der Oestradiol-17β-Spiegel im Urin war in normalen Hunden niedriger als in dysplastischen Hunden nach der Hormon-Injektion. Groessere Hormonmengen kamen im Urin von aelteren Hunden von dysplastischer Abstammung nach Oestradiol-17β-Injektion vor. Diese Resultate zeigen, dass Hunde mit hereditaerer Hueften-Dysplasie eine niedriger als normale Faehigkeit haben, biologisch aktives Oestradiol zu metabolisieren.     

Predicting Wheat Quality Characteristics and Functionality Using Near‐Infrared Spectroscopy

The accuracy of using near‐infrared spectroscopy (NIRS) for predicting 186 grain, milling, flour, dough, and breadmaking quality parameters of 100 hard red winter (HRW) and 98 hard red spring (HRS) wheat and flour samples was evaluated. NIRS shows the potential for predicting protein content, moisture content, and flour color b* values with accuracies suitable for process control (R² > 0.97). Many other parameters were predicted with accuracies suitable for rough screening including test weight, average single kernel diameter and moisture content, SDS sedimentation volume, color a* values, total gluten content, mixograph, farinograph, and alveograph parameters, loaf volume, specific loaf volume, baking water absorption and mix time, gliadin and glutenin content, flour particle size, and the percentage of dark hard and vitreous kernels. Similar results were seen when analyzing data from either HRW or HRS wheat, and when predicting quality using spectra from either grain or flour. However, many attributes were correlated to protein content and this relationship influenced classification accuracies. When the influence of protein content was removed from the analyses, the only factors that could be predicted by NIRS with R² > 0.70 were moisture content, test weight, flour color, free lipids, flour particle size, and the percentage of dark hard and vitreous kernels. Thus, NIRS can be used to predict many grain quality and functionality traits, but mainly because of the high correlations of these traits to protein content.