Evaluation of feedstuffs and aquafeeds

This chapter discusses how to evaluate feedstuffs and feeds. The results of feed evaluation will be used to ensure the production of high quality feeds for fish, crustaceans, and shellfish.IntroductionPhysical evaluationUse of the sensesFeed microscopyMeasurements of feedstuffs bulk densityAttractabilityWater stabilityChemical evaluationProximate analysisMethods of protein evaluationMethods of lipid evaluationMethod of vitamin evaluationMethods of mineral evaluationMethods of energy determinationAnalysis of toxins in feedsMicrobiological evaluationBiological evaluationParameters to be monitored in a feeding experimentSummaryGuide questionsSuggested readings</ul

Processing of alternative feed ingredients in aquaculture feed

Fish meal and fish oil have been used worldwide in aquaculture feed formulations. Production of these ingredients has been relatively constant for decades. However, supplies of industrial fisheries are limited, and unlikely to be able to support increasing demand for these products for a growing aquaculture industry. Finding alternative ingredients therefore, is necessary to address the long-term sustainable growth of aquaculture globally, thereby meeting projected increases in consumer demand for safe, high quality farmed aquatic food. Potential alternative ingredients have been identified, mostly coming from plant-derived nutrient sources, such as seeds, grains, leaves and other agricultural by-products. The use of these alternative ingredients however, may cause anti-nutrient inclusion in the feedstuffs that may interfere with feed utilization and affect the health and production of farmed aquatic products. To get rid of these anti-nutrients, and at the same time improve their nutritive value, various processing techniques (e.g. soaking, moist/dry heat treatment, chemical treatment, dehulling, fermentation), among others may be applied to these ingredients prior to use. Specific obstacles to the use of these ingredients will be the type of treatment, processing procedures and methods required to enhance the nutritive value of the product. Proper evaluation of processed feed ingredients in consideration of factors such as ingredient characterization and functionality, digestibility, palatability, nutrient utilization and/or interference of utilization, influence on immune status and organoleptic qualities, and economic viability need to be done to support their potential effective use in diet formulation. These alternative feed ingredients may offer sound potential when used in the right application. The priorities and future directions of feed manufacturing and researches on alternative feed ingredients with application of proper processing procedures are discussed in this report. The correct use of alternative ingredients with proper application of the right processing techniques may confer significant nutritional and technical advantages to the feed design and management process and may result in high quality feeds for healthy sustainable aquaculture

Spontaneous spawning, fecundity and spawning periodicity in the donkey's ear abalone Haliotis asinina Linnaeus 1758

Spontaneous group spawning was monitored in wild-caught (WC) and hatchery-bred (HB) abalone broodstock (Haliotis asinina) held in duplicate tanks at 1:3 (male: female) ratio from June 1997 to January 1999. Abalone breeders (mean SL, wild = 69-79 mm, HB = 68-71 mm) were kept in perforated plastic baskets and fed red alga, Gracilariopsis bailinae, to excess given at weekly intervals. Abalone spawned spontaneously year-round. Water temperature during the study ranged from 26-29 degree C. A total of 139 and 128 spawning episodes were recorded for WC and HB group respectively. Spawning in WC group (mean: 7 &#177 0.8) were more frequent in September (1998) and from February to April. Spawning frequency in the HB group (mean: 6.4 &#177 1) was generally high during September (1998) until April. Likewise, egg production was highest during these months. Pooled mean survival from trochophore to veligers stage ranged from 7 to 30% (n=36). Potential fecundity was determined in sacrificed group of HB females (n=21) varied from 6,741-11,902 oocytes g -1 BW. Mean oocyte diameter ranged from 136 to 150 mu m. Bigger females had higher potential fecundity (range: 6.2 to 11 x 105 oocytes individual -1 than smaller females (range: 2.8 to 3.3 x 105 oocytes individual -1). The time interval between successive spawning among animals that spawned more than twice during a 5-month period ranged from 13 to 34 days for the small-size group and from 18 to 37 days for large-size group. In separately stocked HB females (without male), instantaneous fecundity was shown to range between 1,500 and 12,300 eggs g -1 BW (n=16). In contrast to potential fecundity, smaller and younger individuals gave higher 68-71 instantaneous fecundity (range: >3,000 >12,000 oocytes g -1 BW) than the bigger and older individuals (1,500-6,500 oocytes g -1 BW)

Use of thraustochytrid Schizochytrium sp. as source of lipid and fatty acid in a formulated diet for abalone Haliotis asinina (Linnaeus) juveniles

The effects of using thraustochytrid Schizochytrium sp. as source of lipid and fatty acids in a formulated diet on growth, survival, body composition, and salinity tolerance of juvenile donkey’s ear abalone, Haliotis asinina, were investigated. Treatments consisted of diets either containing a 1:1 ratio of cod liver oil (CLO) and soybean oil (SBO) (Diet 1) or thraustochytrid (Diet 2) as source of lipid and fatty acids at 2&nbsp;% level. Natural diet Gracilariopsis heteroclada (Diet 3) served as the control. No significant difference in growth was observed in abalone fed Diet 3 (SGR: 5.3&nbsp;% BW day−1; DISL: 265&nbsp;μm&nbsp;day−1) and Diet 2 (SGR: 5.2&nbsp;% BW day−1; DISL: 255&nbsp;μm&nbsp;day−1). Survival ranged from 78 to 85&nbsp;% for all treatments and was not significantly different from each other. A 96-h salinity stress test showed highest survival of 84&nbsp;% in abalone fed Diet 2 compared with those fed diets 1 and 3 (42&nbsp;%). The high growth rate of abalone fed Diet 2 and high tolerance to low salinity could be attributed to its high DHA content (8.9&nbsp;%), which resulted to its high DHA/EPA ratio of 10.5&nbsp;%. These fatty acids play a significant role in abalone nutrition. The fatty acid profile of abalone meat is a reflective of the fatty acid profile of the oil sources in the diet. The present study suggests that the use of Schizochytrium oil in lieu of CLO and SBO can support good growth of abalone which is comparable with abalone fed the natural seaweeds diet

Abalone hatchery

This manual contains information on abalone hatchery operation, including site selection, design, culture of natural food, broodstock management, spawning, nursery, packing and transport, and profitability analyses