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Shrimp waste and marine waste as substitutes of fish meal in broiler diet

A total of 192, 14 days old as hatched broilers were fed ad libitum up to 56 days of age, on a control diet with 12% fish meal (FM) and 3 test diets; shrimp waste (SW) and/or marine waste (MW) and equal mixture of SW and MW completely replace dietary FM to have their effects on performance. Live weight and feed conversion improved and feed intake depleted on test diets than that on control. The test diets did not affect survivability of broilers. Complete replacement of FM by SW and/or MW reduced feed cost and production cost with increased profitability of raising broilers. Meat yield decreased on test SM and MW diets, but equal mixture of SM and MW, gave similar meat yield to that on control. It was concluded that equal mixture of SM and MW might be better, economic and efficient substitute of FM.DOI: http://dx.doi.org/10.3329/bjas.v40i1-2.10785Bang. J. Anim. Sci. 2011. 40 (1-2): 18-22

Effect of complete replacement of fishmeal by dehulled soybean meal with crude attractants supplementation in diets for red sea bream, Pagrus major

A feeding trial was carried out to develop a non fishmeal practical diet for red sea bream (Pagrus major) by gradually replacing fishmeal protein with dehulled soybean meal (DSM). Five isocaloric (22KJg−1) diets were prepared by replacing 0 (FM100), 70 (FM30), 80 (FM20), 90 (FM10) and 100% (FM0) of the fishmeal protein with DSM. Based on our recent findings, all the replacement diets were supplemented with 10% fish soluble (FS), 5% krill meal (KM) and 5% squid meal (SM) to act as attractant and complement amino acids. Triplicate groups of fish (7.3g) were stocked in 100-l polycarbonate circular tanks at a rate of 15 fish per tank. Fish were fed the respective test diets to satiation twice a day for 56days. At the end of the feeding trial, no differences (P>0.05) were found on final weight, weight gain (%) and specific growth rate (% day−1) of fish fed FM100, FM10 and FM0 diets. The growth parameters were significantly (P<0.05) better in fish fed FM30 and FM20 diets compared to FM100 and FM0 diets. Although feed intake value in diet FM30 was significantly higher than that of FM100, these values did not differ significantly from the rest of the diets. There were no significant difference in feed efficiency ratios and protein efficiency ratios among dietary treatments. Whole body proximate compositions and somatic parameters were also not influenced (P>0.05) by the dietary treatments. Although wide variations in some of the blood parameters were observed, no significant alteration was identified among the treatments except for those of plasma total protein and triglyceride, which were significantly increased in fish fed FM0 diet. Dietary treatments had no significant effects on serum cortisol and oxidative stress parameters of fish compared to the control. Based on the present experimental condition, it is concluded that DSM supplemented with FS, KM and SM could completely replace fishmeal in the diets for juvenile red sea bream without any adverse effects on fish performance.

Germ Cell Depletion During Embryogenesis Does Not Affect Subsequent Gonadal Differentiation in Goldfish.

In mammals, the germ line is essential for early folliculogenesis, and thus germ cell deficient animals fail to maintain ovarian differentiation. However, in teleosts, the roles of germ cells in the regulation of sex determination and differentiation are less well understood. Recent reports suggest that germ cell numbers influence ovary fate determination in zebrafish. Fish that lack germ cells or have only a single transplanted primordial germ cell (PGC) develop as phenotypic males. However, as sex determination and gonadal differentiation differ among teleost species, this phenomenon may be restricted to zebrafish or juvenile undifferentiated gonochoristic species. Here, we examined whether germ cells are necessary for gonadal differentiation in goldfish, a gonochoristic species that possesses XX-XY genetic sex determination. Our first step was to isolate the dead end (dnd) gene, which is necessary for the proper migration and survival of PGCs, and to design an anti-sense morpholino (MO) to this gene. Then, we compared germ cell development at 5 months in uninjected controls and in fish derived from embryos injected with dnd-MO at the 1-4 cell stage. In contrast to zebrafish, goldfish without germ cells developed either an ovary or a testis. Two types of gonad were identified: one was flat, wide and transparent, the other was narrow and string-like. Histological analysis showed the former to be an "empty ovary" with a clear ovarian cavity, while the latter was an "gempty testis" with a tubular structure. Thus, germ cells are not essential for gonadal fate determination in goldfish. In a subsequent experiment, we tested whether function was restored to these empty gonads in germline chimeras produced by transplanting a single PGC. Donor PGCs from embryos with an albino phenotype were labeled using gfp-nos1 3'UTR mRNA injected at the 1-4 cell stage. The embryos were enzymatically dissociated at the early somite stage and a single PGC was transplanted into each host embryo (wild type phenotype), which had been injected with dnd-MO. These germline chimeras developed either an ovary or a testis with a fully mature gonad on one side and an empty gonad on the other, showing the typical features of single PGC-transplanted chimeras. Cross breeding with male chimeric and female albino fish yielded 100% albino offspring, indicating that complete germ line replacement had occurred and the PGC-transplanted chimeras had recovered gonadal function. These findings suggest that, in goldfish, phenotypic sex is determined by somatic cells that express the relevant genes under genetic sex control rather than an interaction between germ cells and somatic cells. The generation of germline chimeras provides a valuable approach to investigating the contribution of germ cells to sex determination and differentiation, gonad formation and gametogenesis in teleosts, because of the ability to completely replace the germ line. (platform)

Response to Foss et al., ‘Care should be taken when promoting microbicide use among sex workers who are able to use condoms consistently’

Mathematical modeling analyses by ourselves and Foss et al. predicted that vaginal microbicides could substantially reduce the risk of HIV acquisition. Our analysis purposely considered a high-risk group of women namely female sex workers (FSW) in a high prevalence resource-constrained setting. We determined that increasing microbicide use would have a greater impact on reducing risk than increasing microbicide efficacy. We also quantified the break-even threshold for the level of condom replacement that could be tolerated given microbicide efficacy and usage so that the risk of HIV acquisition would not increase .We predicted that even if the microbicides that become available are low to moderately effective the probability that risk in FSW would increase (as a result of replacing condoms with microbicides) would be low. Furthermore in our threshold analysis we considered the worst-case scenario of complete condom replacement; if only partial condom replacement occurred results would be more optimistic. Our conclusions assume low-to-moderate condom use before the introduction of microbicides. (excerpt)

Incomplete replacement of docosahexaenoic acid by n-6 docosapentaenoic acid in the rat retina after an n-3 fatty acid deficient diet

When sources of n-3 fatty acids are not present in the diet, nervous system docosahexaenoic acid (22:6n3) is replaced by docosapentaenoic acid (22:5n6). Dams were fed either an n-3 deficient diet or one containing alpha-linolenic acid (18:3n3) and 22:6n3 throughout pregnancy and lactation. Their male offspring at weaning also received either the n-3 deficient or n-3 adequate diets and were sacrificed at 5, 10, 20, 50 and 91 days of age. Retinal lipids were extracted and analysed by gas chromatography for fatty acyl content. The percentage of retinal 22:6n3 increased continuously over the 13 week course of the experiment but reached its maximal concentration around day 20. Non-reciprocal replacement of 22:6n3 by 22:5n6 was observed at postnatal day 20 and 50 but not at other time points. Complete replacement of 22:6n3 was apparent if elevations in both 22:5n6 and docosatetraenoic acid (22:4n6) were considered. These data indicate that during the rapid period of accretion of retinal 22:6n3 around postnatal day 20, the supply of 22:5n6 to the retina was inadequate to completely replace 22:6n3 in n-3 deficient rats.

EVALUATION OF LOW GLUCOSINOLATE — LOW ERUCIC ACID RAPESEED MEALS AS PROTEIN SUPPLEMENTS FOR YOUNG GROWING PIGS, INCLUDING EFFECTS ON BLOOD SERUM CONSTITUENTS

Forty-nine 4- to 5-wk-old pigs, averaging 7 kg in weight, were allotted to seven treatment groups. Rapeseed meals (RSM) from two cultivars of double-low (low glucosinolate-low erucic acid) Brassica napus rapeseed processed at one plant, one of the same cultivars processed at a second plant, and a low erucic acid B. campestris cv. Span were compared as partial or complete replacements (up to 22% of the diet) for soybean meal (SBM) in diets of starting–growing pigs. Overall results for feed intake, daily gain and efficiency of feed conversion indicated that RSM from a double-low cultivar (now licensed as Tower) may completely replace SBM in diets for starting–growing pigs with no depression in performance. Results from un unlicensed cultivar (1788) were inconsistent, with differences possibly associated with residual hexane in one sample of meal. Digestible energy and nitrogen, metabolizable energy and nitrogen retention did not differ between treatments. A profile of 14 blood serum constituents was obtained from individual pigs 3 and 9 wk after the start of the experiment. Thyroxine (T4) values were lower (P &lt; 0.05) for all treatments when RSM was completely substituted for SBM. Protein-bound iodine values did not differ significantly between treatments but followed the same trends as T4. Results suggest that all RSM samples were goitrogenic to some degree. Blood serum constituents that correlated with average daily gain at [Formula: see text] were calcium, total protein, albumin, albumin:globulin ratio and lactate dehydrogenase. The results suggest that RSM from low glucosinolate–low erucic acid rapeseed, when it becomes commercially available, may be fed at higher levels than currently recommended.