Effects of fish meal replacement with full-fat soy meal on growth and tissue fatty acid composition in Atlantic cod (Gadus morhua)

Atlantic cod of initial mean weight approximately 220 g were fed a control diet and three diets in which fish meal (FM) was replaced with increasing levels of full-fat soybean meal (FFS) supplied at 12, 24, and 36% of dry diet, for 12 weeks. There were no significant differences in final weights, but the specific growth rate (SGR) was significantly higher in fish fed the control (FFS0) diet compared to fish fed the FFS12 and FFS36 diets, and the feed conversion ratio (FCR) was significantly lower in fish fed the FFS0 diet compared to the other three treatments. The fatty acid (FA) compositions of the cod muscle and liver were highly affected by dietary treatment, and linear relationships between dietary and tissue FA concentrations were shown for some of these. Moreover, selective utilization or accumulation in the tissues of specific FA was suggested by the results.     

Bioactive compounds of grapefruit (Citrus paradisi Cv. Rio Red) respond differently to postharvest irradiation, storage, and freeze drying

In the present study, the effect of irradiation, storage, and freeze drying on grapefruit bioactive compounds was investigated. Grapefruits were exposed to one of two irradiation doses: 0 (control) or 300 Gy (137Cs, a proposed treatment against fruit flies) and then stored for up to 6 days. At the last storage time point (6 days after harvest), grapefruit pulp from control and irradiated fruits was freeze-dried. Bioactive compounds were extracted from Rio Red grapefruit pulp and analyzed with reverse phase liquid chromatography while volatile compounds were analyzed using gas chromatography. Freeze-dried pulp from irradiated fruits had a higher (P < or = 0.05) flavonoid content (naringin and narirutin) as compared to the freeze-dried pulp from the control fruits. Freeze-drying treatment reduced (P < or = 0.05) the lycopene content, but the reduction (P < or = 0.05) in beta-carotene content occurred only in the control fruit. Reduction in d-limonene and myrcene was observed in the irradiated fruits at 6 days after harvest and in the freeze-dried samples. These results warrant testing of the effect of postharvest treatments and processing on bioactive compounds in functional systems as they have varied effects on different bioactive compounds of grapefruit.     

Sperm Pre-Incubation Prior to Insemination Affects the Sex Ratio of Bovine Embryos Produced in vitro

The objective of the present study was to determine whether sperm incubation prior to oocyte insemination in vitro affects the sex ratio of resulting blastocyst. Cumulus–oocyte‐complexes (COCs) collected from slaughterhouse ovaries were matured in vitro and inseminated with frozen‐thawed semen of three proven artificial insemination (AI) bulls pre‐incubated in vitro in Sperm‐Talp for 6 and 24 h. On day‐9 blastocysts were collected and processed for sex determination. More than 80% of blastocyst were successfully sexed. There were no significant differences in cleavage and blastocyst rates using sperm pre‐incubated for 6 h as compared with the 0‐h pre‐incubation control group. The cleavage and blastocyst rates were significantly lower in the 24‐h pre‐incubation group. The male to female ratio, when compared with the theoretical 1 : 1, differed significantly in favour of females among hatched (viable) blastocysts derived from sperm pre‐incubated for 24 h prior to insemination as well as among all blastocytsts in the 6‐h group. Moreover, when the sperm treatment was considered, the sex ratio was affected only among hatched blastocysts in 24‐h pre‐incubation group. It was concluded that prolonged sperm pre‐incubation influences the rate of development and the sex ratio among hatched blastocysts.     

Rapid confirmatory identification of Mycobacterium bovis using a dot blotting immunodetection technique

A safe, cost effective and accurate immunodetection technique for the rapid identification of Mycobacterium bovis colonies is described. One hundred and thirteen M. bovis isolates were differentiated from other species of mycobacteria using a M. bovis specific monoclonal antibody, with nitrocellulose membrane as the solid support. The technique confirms M. bovis identification in only 4 h compared to 3 weeks for conventional antibiotic sensitivity tests.     

Antigenicity of structural components from porcine transmissible gastroenteritis virus

Pregnant sows were inoculated with inactivated transmissible gastroenteritis virus and with preparations of virus surface projections and subviral particles derived by detergent treatment of the virus. Neutralising antibody was demonstrated in serum and colostrum from animals that received whole virus or preparations of surface projections whereas subviral particles failed to stimulate neutralising antibody formation. Similar results were obtained with serum from rabbits inoculated with whole virus and structural components. All three preparations stimulated the formation of agglutinating antibodies, as demonstrated by sedimentation analysis and filtration studies with radiolabelled virus.The immunoglobulin classes responsible for neutralising antibody activity in sows inoculated by the intramammary route were examined. In each case where the immunoglobulin class was determined, IgG was found. One sow that received surface projections also had IgA with neutralising activity in her colostrum. In contrast, infection of sows with live whole virus resulted in neutralising antibody of the IgG, IgM and IgA classes.