Ian Forster

Aquafeeds and the environment: policy implications

Abstract Aquaculture feeds and feeding regimes can play a major role in determining the quality and potential environmental impact or not of finfish and crustacean farm effluents. This is particularly true for those intensive farming operations employing open aquaculture production systems, the latter including net cages/pen enclosures placed in rivers, estuaries or open-water bodies, and land-based through-flow tank, raceway or pond production systems. This is perhaps not surprising since the bulk of the dissolved and/or suspended inorganic and/or organic matter contained within the effluents of intensively managed open aquaculture production systems are derived from feed inputs, either directly in the form of the end-products of feed digestion and metabolism or from uneaten/wasted feed, or indirectly through eutrophication and increased natural productivity. So, as to limit the potential negative environmental impacts of feeds on aquaculture effluents, the major approaches taken by government authorities within major aquaculture-producing countries have included (1) requiring the treatment of farm effluents prior to discharge, through the use of settlement basins, specific filtration devices, waste water treatment systems, etc., (2) limiting the concentration of specific dissolved/suspended inorganic/organic materials and/or nutrients contained within the effluent discharged from the farm, (3) establishing maximum permissible amounts of specific nutrients (such as total nitrogen or phosphorus) that the farm is able to discharge over a fixed time period, (4) limiting the total number of licenses that can be issued and/or size of farm, depending upon the vicinity of other farming operations and the assimilative environmental carrying capacity of the receiving aquatic ecosystem, (5) limiting or fixing the total quantity of feed the farm is able to use over a fixed time period, (6) fixing maximum permissible specific nutrient levels within the compound feeds to be used to rear the species in question, (7) banning the use of specific potentially high-risk feed items such as fresh/trash fish and invertebrates, (8) banning the use of certain chemicals on-farm, including specific chemical therapeutants/drugs and chemicals (i.e., potentially toxic herbicides and pesticides, etc., (9) prescribing minimum feed performance criteria, such as specific levels of allowable dust/fines, feed efficiency or nutrient digestibility, (10) requiring the use of specific Codes of Conduct, including appropriate Best/Good Management Practices for farm operations, including feed manufacture and use, and environmental management, (11) requiring the development of suitable farm/pond sediment management strategies for the storage and disposal of sediments, or (12) requiring the implementation of an environmental monitoring program. The paper describes the merits and demerits of each of the above initiatives, with specific country examples, and attempts to offer guidance for the development of government policies aimed at regulating off-farm effluents and outputs rather than regulating on-farm feed inputs and feeding practices.

Rendered meat and bone meals as ingredients of diets for shrimp Litopenaeus vannamei (Boone, 1931)

Abstract The nutritional quality of three sources of rendered meat and bone meals (MBM) was evaluated as feed ingredients in diets for juvenile Litopenaeus vannamei . Two trials were conducted in this work: an in vivo apparent digestibility trial and a growth trial. The apparent digestibility coefficients for dry matter, crude protein and amino acids of diets containing fixed percentages of each protein source were determined using the marker (0.5% chromic oxide) method. A separate feeding trial was conducted to ascertain the maximum level of replacement of high-quality Norwegian fish meal in diets for this species. Nine dry diets were formulated to contain each protein source at 25%, 50% and 75% levels of replacement of fish meal. A 10th diet, the control, contained no meat and bone meal. Fish oil was adjusted to maintain equal lipid levels among the diets. The growth and survival of shrimp fed each diet for 8 weeks were determined. Responses of shrimp to dietary MBMs differed for both the digestibility and the growth trials. The apparent digestibility coefficients of dry matter, protein and amino acids were lower relative to the fish meal for the diets containing the three MBMs, and this difference was statistically significant for two of them. The growth trial, however, revealed that MBM effectively replaced between 25% and 75% of fish meal, depending on which MBM was used. A general decrease in growth above 25% replacement was observed for all MBM sources. The relative rankings of the three MBMs were different based on digestibility and growth performance data, indicating that digestibility itself is insufficient to explain the reduction in growth response relative to dietary fish meal.

Nutritional Quality of Fish Meals Made from By-Products of the Alaska Fishing Industry in Diets for Pacific White Shrimp (Litopenaeus vannamei)

Abstract The nutritional quality of ten commercially available white fish meals made from by-products of the Alaska fish processing industry (primarily pollock) was determined. Pelleted feeds were manufactured containing these meals in complete replacement of a low-temperature processed Norwegian fish meal (control). These feeds were fed to triplicate tanks of Pacific white shrimp at the facilities of the Oceanic Institute for a period of ten weeks. At the end of the trial, the growth, feed conversion ratio and survival data were subjected to analysis of variance procedures. The final weight of the shrimp was more than ten times the initial and mean survival was 97%. There were no significant differences in performance parameters among the treatments. It is concluded that the nutritional quality of Alaska white fish meals is equivalent to the highest standard in the industry and are of suitable quality for inclusion in commercial shrimp feeds.

A Comparative Study of the Physical and Biological Properties of Commercially-Available Binders for Shrimp Feeds

Abstract In accordance with binder manufacturers recommendations, commercial binders were added to a standard control feed to create twelve binder treatments. These binder treatments and their controls were processed under standard conditions to determine if the binders could improve the stability of a shrimp feed. To make that determination, pellets processed with the added binder treatment were compared with their control (no binder), after being immersed in water for four time periods (30, 60, 120, and 240 minutes) and compared for pellet structure and nutrient leaching (crude protein, lipid, and ash). Hydro-Gard and Compact-PBX were the only two binders that showed significant (P< 0.05) improvement in pellet structure over their controls in all four time periods. From the pellet structure data, the binders were ranked from the most to the least stable as follows: Maxi-Bond H20, Agrimer Mix, Maxi-Bond, Pell-Tuff, Compact-PBX, Hydro-Gard, Biodone AQ90, Carbo Binder, A.MAS, Pro Blend, Aqua-Tec “N,” and Nutri-Binder. All binders were ranked according to the amount of protein retention after the four leaching periods. The leaching data for protein showed a general trend toward higher protein retention in diets containing binders, compared to their controls. Protein remaining in the leached pellets was especially evident in the urea formaldehyde binders (Compact-PBX and Maxi-Bond) and in the natural and hydrophilic polymers (Hydro-Gard). These binders retained significantly (P <0.05) more protein than their controls in all time periods. The binders were ranked from the greatest amount of protein retained to the least protein retained, as follows: Maxi-Bond, Maxi-Bond H20, Pell-Tuff, Compact-PBX, Agrimer Mix, Hydro-Gard, Carbo Binder, Aqua-Tec “N,” A.MAS, Biodone AQ90, Pro Blend, and Nutri-Binder. The binders were also tested for pellet durability index (PDI), pellet hardness, pelleting efficiency, and the cost of binder inclusion per metric ton of feed. There were no significant differences (P >0.05) in pellet hardness and pelleting efficiency among all binders tested. The least expensive binder was a urea-formaldehyde binder (A.MAS), which cost

Temperature and Food-Ration Optimization in the Hatchery Culture of Juveniles of the Pacific Geoduck Panopea generosa

4.41 per ton of feed. Agrimer Mix and Biodone AQ90 were ranked the top binders for PDI and were significantly (P <0.05) more durable than Nutri-Binder but not significantly (P >0.05) different from all other binders. Shrimp average final weight (g) at eight weeks for Pro-Blend (7.80), Carbo Binder (7.52), Agrimer Mix (7.50), Biodone AQ90 (7.33), and the control (7.27) ranked first through fifth for growth. Shrimp fed binders containing urea-formaldehyde, Maxi-Bond, Compact-PBX, and Pell-Tuff, when added above 0.5% reduced shrimp final weights and weekly growth. Shrimp survival in this trial was very high (100-91.7%) and there were no significant (P >0.05) differences among treatments for survival. Feed Conversion Ratios (FCR) ranged from Pro-Blend (1.46:1) to Pell-Tuff (2.12:1) where these two treatments were significantly (P <0.05) different from each other.

Use of Fish Hydrolysates and Fish Meal Byproducts of the Alaskan Fishing Industry in Diets for Pacific White Shrimp Litopenaeus vannamei

ABSTRACT n This research examined the individual effects of temperature and ration on growth and survival of juveniles of the Pacific geoduck Panopea generosa Gould, 1850, in two separate experiments. Growth parameters measured included shell length, daily shell increment, individual total body wet weight, specific growth rate, individual total body dry weight, and total body ash-free dry weight (AFDW). Larvae in all treatments were fed a binary microalgal diet of Chaetoceros muelleri and Tisochrysis lutea mixed at a 1:1 ratio by AFDW. The temperature experiment examined the effect of four temperatures (7°C, 11°C, 15°C, and 19°C) using two geoduck cohorts. One cohort was comprised of larger juveniles (mean initial shell length ± SE, 3.22 ± 0.05 mm) and the other included smaller individuals (0.54 ± 0.01 mm) which were cultured for 28 days and 21 days, respectively. Using a separate cohort, the foodration experiment examined the effect of nine rations (0.0, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, and 128.0 × 106 equivalent T. lutea cells per individual per day) on four size classes of geoduck juveniles obtained from the same spawning batch (mean initial shell length ± SE, size class 1,2.34 ± 0.04 mm; size class 2, 3.32 ± 0.04 mm; size class 3,4.13 ± 0.04 mm; and size class 4, 4.98 ± 0.04 mm) for 7 days. On the final sampling day, there were significant differences among all four temperatures for all growth parameters except AFDW, with each parameter increasing significantly for each increase in temperature. For AFDW, there were no significant differences between 7°C and 19°C, nor between 11°C and 15°C, with the first set of two temperatures producing juveniles with significantly less AFDW than the latter set. In general, optimal ration levels increased with increasing geoduck size. To optimize growth in shell length, individual total body wet weight, and/or individual total body dry weight, the following rations are recommended for size classes 1, 2, 3, and 4, respectively: 4.0 or 8.0, 8.0, 16.0 or 32.0, and 32.0 or 64.0 × 106 equivalent T. lutea cells per individual per day. Refinement of an understanding of optimum juvenile geoduck culture conditions contributes to the general knowledge of the species’ physiology and helps maximize the commercial hatchery production of geoduck seed.

Classification and Quantification of Phospholipids and Dietary Effects on Lipid Composition in Pacific White Shrimp Litopenaeus vannamei

Abstract We determined the suitability of four fish hydrolysates and two fish meals (Pacific halibut Hippoglossus stenolepus and arrowtooth flounder Atheresthes stomias; all derived from byproducts of the Alaskan fishing industry) as replacements for menhaden fish meal in shrimp diets. A control diet (30% crude protein; 8.5% crude lipid) was produced with menhaden meal (13% of diet). Experimental diets were manufactured by using each hydrolysate or fish meal to replace 50% of the menhaden meal on an isonitrogenous basis. Each diet was fed to Pacific white shrimp Litopenaeus vannamei in an outdoor, zero-water-exchange system for 8 weeks. Final weight, survival, feed efficiency, and growth rate were compared among treatments by analysis of variance. The final weights and growth of Pacific white shrimp fed two of the hydrolysates (one acidified to pH 3.8 and left in a liquid state; the other acidified, then neutralized to pH 6.5 and drum-dried) and the two fish meals were not different from those of shrimp f...

Determination of microbial community structures of shrimp floc cultures by biomarkers and analysis of floc amino acid profiles

Abstract The phospholipid (PL) composition of Pacific white shrimp Litopenaeus vannamei and the diets on which they were reared during an 8-week indoor feeding trial was characterized. Nine PL classes, including phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidic acid, and phosphatidylserine, were detected and quantified in shrimp, diets, and feed ingredients by high-performance liquid chromatography. Total PL comprised the majority of total lipid—over 69.5% in shrimp tail muscle and over 60.1% in the shrimp whole body. The PC, PE, and PI classes were the most abundant, comprising over 40, 35, and 15%, respectively, of the PL in shrimp tails. Cardiolipin and ceramides were also detected in the shrimp whole body. Dietary crude protein content (40% versus 35%) significantly affected the PL composition of the shrimp whole body. Addition of shrimp floc (suspended particles from shrimp culture) to a 40% crude protein diet yielded higher Pacific white shrimp growth a...