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The nutritional value of whole, dehulled, extruded, dehulled–extruded and micronized feed peas, and extruded canola meal, included at a 30% concentration as ingredients in diets for juvenile blue shrimp was assessed. Pea meals replaced a portion of soybean meal and wheat (1:3 parts) on an isonitrogenous and isoenergetic basis, and similarly extruded canola meal replaced a portion of soybean meal, fish meal and wheat (1:2:3 parts) of a control diet. After 28 days, the shrimp almost tripled their weight on the experimental diets. Performance was unaffected by dehulling, except for a slight increase in feed consumption and lower protein efficiency ratio (PER). Extrusion cooking had no effect on growth and survival but significantly improved feed conversion and PER. The micronized pea diet produced the highest feed intake and growth rate. Response to the diet containing extruded canola meal was similar to that of the control diet. Ingredient apparent dry matter digestibility (IADMD) ranged from 80.7% for micronized peas to 92.4% for dehulled–extruded peas, and was 79.4% for extruded canola meal. Higher IADMD coefficients were obtained for extruded pea meals as a result of starch gelatinization. Ingredient apparent protein digestibility (IAPD) ranged from 79.1% to 85.4% and did not differ significantly amongst the test meals. The test ingredients also conferred differential water stability properties with the whole-extruded peas ingredient containing diet having the lowest dry matter and crude protein (CP) loss following a 1-h immersion in water. This study showed that whole raw feed pea is a very acceptable ingredient for blue shrimp diets; extrusion cooking improved feed conversion ratio and PER, and micronizing peas enhanced feed intake, while dehulling had no effect.

The growth rate and survival of the Capilano (hatchery) and Harrison (wild) strains of chinook salmon ( O. tshawytscha ) of British Columbia and their hybrids reared in confinement were compared both during the fresh-water phase and the sea-water phase. Eggs stripped from the Capilano females had better fertility, fingerlings of the Capilano strain were heavier at 25 weeks of age and had a higher average specific growth rate. The Capilano fish were also heavier both in live weight and gutted weight after 1.5 years in sea-pens. No heterosis was detected for any of the traits measured. Cross-means for body weight and specific growth rate tended to be similar to the strain-of-sire mean.

In order to study the inheritance of flesh pigmentation in chinook salmon, a 6×6 factorial cross was set up by fertilizing eggs from three white (W)- and three red (R)-fleshed chinook salmon with milt from three W- and three R-fleshed salmon to give 36 full-sib families. During the last 7 months before colour-scoring all fish were fed a diet supplemented with astaxanthin added in an oil carrier. Flesh pigmentation was measured against a colour fan at approximately 120 weeks of age and scored on a scale of 1–8. Progeny from RR matings were more pigmented than progeny from WW matings and the pigmentation in the progeny from the crosses was more dependent on the pigmentation of the dam than the sire. There was no significant correlation between the degree of pigmentation and the lipid concentration of the flesh. The results demonstrated that chinook salmon, fed the same diet containing astaxanthin, may show wide variation between strains as well as among families within strains in ability to utilize the dietary pigment. Such heterogeneity among parents within strains suggests that the expression of pigmentation is controlled by a small number of genes with large non-additive effects.

This study was undertaken to assess the nutritional value of marine fish protein sources processed in different ways for juvenile chinook salmon reared in fresh water. The protein sources compared were a freeze-dried pollock muscle and euphausid mix (9:1) (FPE), and three whole herring meals processed differently from a common lot of raw herring. A casein-gelatin mix supplemented with arginine and DL-methionine (CS) served as a reference protein source. The five protein sources were each tested at three protein concentrations in isocaloric diets. FPE was also assessed at two additional protein levels. Protein was replaced by dextrin and glucose on an estimated metabolizable energy basis. Each diet was fed to duplicate groups of fish held at 10.5°C on a natural photoperiod for 42 days. All fish were fed daily to satiation. Two groups received Oregon moist pellets (OMP-2), a practical hatchery diet. Each of the various methods employed to evaluated protein quality yielded different relative values in comparison to FPE, which was judged to be the best protein source on the basis of growth rate response and assays based on body protein gain. Low temperature (75°C) dried herring meal had slightly reduced protein quality compared to freeze-dried herring meal, whereas the high temperature (150°) dried meal had dramatically reduced protein quality. High estimates of protein quality were obtained for CS. However, this protein source was not as palatable as the low temperature dried marine protein sources and consequently growth was reduced.