No abstract

No abstract

Total replacement of fishmeal using marine co‐product meals in the diets for white shrimp Litopenaeus vannamei and its effects on growth, feed utilization and muscle HUFA and sterol composition were assessed in a 45‐day feeding trial with juvenile shrimp (0.32 g mean initial weight). Eight dietary treatments were tested: a control diet containing fishmeal (FM), a commercial shrimp diet as external reference and six diets where the FM in the control diet was totally replaced by pen shell scallop viscera (Pinna rugosa), squid viscera (Dosidicus gigas) or whole chub mackerel (Scomber japonicus) meals, produced by two methods: (i) cooking followed by grinding and drying and (ii) grinding followed by drying. Survival in all treatments was above 92%, except in the commercial diet (77%). The growth response, feed utilization and chemical composition of shrimp varied among the treatments and were affected in different ways by the by‐products and the meals preparation process. Growth and feed intake were significantly higher in shrimp fed diets containing cooked‐dried squid and pen shell scallop viscera meals, and whole mackerel meal produced by grinding followed by drying. Muscle fatty acid profiles were improved for human consumption when these ingredients were used, compared with the diets containing FM.

The effect of including 5% marine by-product meals in feeds of laying hens on egg production, composition and sensory characteristics was tested. Marine by-product meals were prepared using two methods: (i) cooking (100°C/10 min) followed by drying (60°C/24 hr) or (ii) grinding followed by drying. The raw materials used for meal production were scallop or squid viscera, shrimp heads or whole mackerel. A total of 108 laying hens were allocated to nine diet treatments; one control diet (corn and soya bean based) and eight experimental diets, containing 95% of the control feed and 5% of the experimental meal for three weeks. Daily intake was higher in hens fed the dried mackerel and cooked shrimp meals. All the experimental treatments showed significantly higher concentration of n-3 HUFA in yolk reserves and phospholipids compared to the control (0.12-0.13 g per 100 g), especially those with scallop or squid prepared by both methods (0.53-0.95 g per 100 g). Scallop, squid and shrimp meal inclusion in the feed produced eggs with more astaxanthin (0.22 mg per 100 g) while this carotenoid was absent in the control and mackerel treatments. Visual evaluation of raw yolk colour increased with the inclusion of marine by-product meals with higher values in hens fed shrimp heads (13), followed by scallop viscera (11), squid viscera (9), and with similar values for mackerel and control (4). The taste, aroma, texture and colour of cooked eggs from different treatments were not statically different when evaluated by a panel of 60 untrained people. These results suggest that meals from marine by-products are a better alternative for improving egg yolk composition by increasing n-3 HUFA when compared to fishmeal as they also increase astaxanthin and yolk pigmentation without affecting egg sensory characteristics.

Objective. The objective of the study was to determine the composition of fatty acids in milk of Creole goats in an extensive production system in an arid region of the peninsula of Baja California and compare it to two seasons of the year (rainy and dry). Materials and methods. Sampling was conducted during the dry season (June) and after the rainy season (December) in the municipality of Comondú in Baja California Sur. The extensive production system used involved releasing goats to roam freely in the rangeland to graze for food, and no additional food or supplements were provided. Results. The most abundant fatty acids were saturated fatty acids (66.3 and 70.9% in the rainy and dry reasons, respectively). The most abundant of these were palmitic, myristic, and stearic acid in both seasons. Monounsaturated fatty acids (15-20%) were the most numerous in terms of isomers, but mostly in low concentrations. The largest average constituent of polyunsaturated fatty acids (5-6%) was linoleic acid (3%) and alpha-linolenic acid (1.2%) in both seasons. Branched, fatty acid concentrations were highly variable; the only stable constituents were C15:0 iso (1.5%) and C16:0 anti-iso, with 0.7% of total fatty acids. Conclusions. The seasons in this extensive production system significantly effected the composition of most monounsaturated and branched fatty acids in goat milk; however, saturated and polyunsaturated showed only a few compositional changes in abundance of fatty acids. Moreover, season effects were not significant on the total fatty acid content, except for branched fatty acids and omega-3.