By-product Feed Research Articles

Tuna byproducts as a fish-meal in tilapia aquaculture

Potentiality of the use of tuna byproducts as a fish-meal replacement on Nile tilapia (Oreochromis niloticus) was examined for 84 weeks by tracking the concentrations of cadmium and mercury in the internal organs, muscles and fish whole body through generation including their immature eggs and their larvae. The results confirmed that the tuna byproducts can be used as a fish-meal substitute in tilapia aquaculture, because their acceptable ranges for cadmium and mercury consequently did not exceed the food safety values (both < 0.5 mg kg−1), despite their proportional increases in the fish body. The use of tuna byproducts as a protein source is expected to reduce the cost of feed with other fishmeal substitutes in tilapia aquaculture. However, fish (flounder) indiscriminately consuming tuna byproduct feed were prohibited and recalls of sales were issued by the government (July 2018, Republic of Korea), as the threshold for mercury in the fish bodies had been exceeded (0.6–0.8 mg kg−1). Further study of the use of tuna byproducts as fishmeal replacements for other species in aquaculture is needed, as concentration ratios can vary depending on the species.

Effect of Molasses and Dried Orange Pulp as Sheep Dietary Supplementation on Physico-Chemical, Microbiological and Fatty Acid Profile of Comisana Ewe's Milk and Cheese.

The use of agro-industrial by-products for ruminant feed represents both an economical and environmental convenient way for reducing waste discharge and waste management costs for food industries. Large amounts of waste from citrus processing industries are available in Sicily, Italy. In the present study, the effect of dried citrus pulp as sheep dietary supplementation was evaluated on physico-chemical, microbiological and fatty acid composition of resulting milk and cheese. Pelleted feed integrated with molasses and blond orange pulp, replacing cane molasses, beet pulp and part of the maize and sunflower in ration, were administrated to ewes as an experimental treatment The experiment involved sixty Comisana breed sheep divided into two groups and two feeding trials (experimental and control). Ewe's milk and cheese samples were collected from January to April and analyzed for physico-chemical, microbiological and fatty acid profile composition. Results suggested that both the experimental milk and cheese were different from the controls. In particular, an increase of experimental milk yield and fat content were registered whilst the cheese samples exhibited a significant decrease of pH values and an increase in fat and protein contents. In addition, an increase of conjugated linoleic acids as well as of the oxidative stability were observed indicating the beneficial effect of dietary supplementation. Furthermore, among the main microbial groups, the experimental and control samples, no differences were detected. However, with the exception of streptococci, which was found higher in experimental cheeses, and staphylococci, which was significantly reduced by experimental feed. Moreover, the application of culture-independent methods highlighted the dominance of Lactobacillus rhamnosus/casei group in the experimental cheese, suggesting a driving role of the dietary supplementation in the cheese microbiota composition. The present study demonstrated that the inclusion of citrus by-products in the diet of small dairy ruminants is a promising feeding, which could positively affect milk composition and cheese manufacture.

A Nutritional Survey of Commercially Available Grass-Finished Beef

Consumer interest in the source of their food, its environmental footprint, and the impact of diet on health has supported the growth of the grass-finished beef (GFB) industry. Studies have concluded that GFB has distinct nutritional differences from conventionally-finished beef. As the GFB industry continues to expand, it is vital to continue to explore the nutritional complexities and variation in the product. To achieve this, a survey of grass-finishing production systems throughout the USA was conducted, and beef finished on the participating farms was analyzed for its nutritional composition, including fatty acid (FA), mineral and fat-soluble vitamin contents. Samples were analyzed from 12 producers and annual production capacity of farms ranged from 25 to 5,000 cattle, with a mean age of cattle at harvest of 26.8 ± 2.30 mo. An array of finishing diets included grazing exclusively in perennial pasture, incorporating annual forage crops, and feeding a variety of harvested forages with supplementation of non-starch feed byproducts. Beef muscle tissue FA content was analyzed by gas chromatography-mass spectrometry (GC–MS). The mean ratio of omega-6 (n-6) to omega-3 (n-3) FA in samples varied significantly by producer, ranging from 1.80 to 28.3 (P &lt; 0.0001), with an overall sample set median of 4.10. A selection of minerals including iron, magnesium, and potassium were analyzed by ICP emission spectroscopy and mineral content significantly differed by producer for all minerals (P &lt; 0.001). Mean α-tocopherol and β-carotene content was 610.6 µg/100 g beef and 32.2 µg/100 g, respectively. The amount of these antioxidants also varied between producers (P &lt; 0.0001), but tended to be greater in beef finished solely on fresh forages. This survey indicates that commercially available GFB can vary in nutritional composition due to the diverse practices used to grass-finish cattle.

Use of Agro-Industrial By-Products in Animal Feed at Modern and Semi-Modern Farms of Urban Community of Niamey (UCN): State Places

&lt;em&gt;The study was conducted in Urban Community of Niamey at modern and semi-modern farms provided an overview use of agro-industrial by-products in animal feed. Among 57 farms only 17 farms, including 10 beef farms, 2 sheep farms and 5 poultry farms were systematically surveyed. All farm managers are men. 60 and 33% are respectively officials at the level of poultry farms and ruminant farms. Farmers make up 25%, all of which own beef farms. There is also a predominance of adults, 60% at poultry level and 58.33% at ruminant farms. We note the use of a variety of agro-industrial by-products in animal feeds, in this case by-products derived from vegetable processing (wheat bran, exfoliated cotton cake) and animal processing (fish and fish meal ...). There are also some concentrates for poultry feed. Agribusiness by-products are increasingly used in urban livestock production but their valorization needs to be improved.&lt;/em&gt;

Pizzeria by-product: A complementary feed source for Nile tilapia (Oreochromis niloticus) raised in biofloc technology?

In face of all problems regarding to the traditional tilapia food sources and production systems the search for sustainable alternatives have been increasing. Within this context, the aim of this study was to evaluate different inclusion levels of pizzeria by-product meal (0, 20, 40, 60, 80 and 100%) in diets for Nile tilapia (Oreochromis niloticus) reared in biofloc systems. Diets were prepared from a pre-existing commercial diet, milled and re-pelleted, containing different inclusion levels (considering 0% as the control group). A total of 288 tilapia juveniles were randomly stocked (2.90 ± 0.02 g) in 24,100-L experimental units (6 dietary treatments with 4 replicates). Water quality parameters and the planktonic community profile were monitored throughout the feeding trial (38 days). Zootechnical performance of fish fed the 20% pizzeria by-product feed was statistically equal (p > 0.05) to those fed the control feed. Feed conversion ratio was also similar (p > 0.05) between these treatments, as well as with the 40% inclusion group. During the experimental period, seven taxa of planktonic organisms were characterized in the bioflocs. According to economic analysis and performance data, it is possible to successfully include up to 20% of pizzeria by-product meal in diets for Nile tilapia reared in biofloc systems, and 40% inclusion of pizzeria by-product might exhibit a strategic economic benefit to the farms that also commercialize fingerlings.

A novel antibody-based enrichment and mass spectrometry approach for the detection of species-specific blood peptides in feed matrices

Blood is an important animal by-product and an attractive source for animal feed production. However, the outspread of bovine spongiform encephalopathy led to strict regulations on the usage of animal by-products in animal feed. Although, the ban on certain processed animal proteins has been partially abolished in recent years, it is still challenging to distinguish legal from illegal protein additives in complex feed products using analytical methods. To overcome these gaps, this study aimed to develop a tissue-specific and sensitive immuno-based enrichment and mass spectrometry-based detection method to identify haemoglobin peptides of ruminant or porcine origin when mixed in a background of vegetal feed, fish meal, aquaculture feed, blood compounds, or milk powder. Here we report the first analytical method able to species-specifically detect adulterations of as little as 0.05%–1% (w/w) ruminant blood meal in various matrices on a quadrupole-time of flight instrument.

Changes in the milk fatty acid profile of Awassi sheep in response to supplementation with agro-industrial by-products

Awassi dairy sheep farmers in the Middle East are facing high feed costs, particularly during the milk production season, along with large fluctuation in grain and straw prices.Incorporating agro-industrial byproducts into the diet of Awassi dairy sheep can help to balance diets and decrease costs. But it may affect milk quality through changes in the fatty acid profile. Six experimental diets were compared to a control diet in the research station of the International Center for Agricultural Research in the Dry Areas (ICARDA) in Tal Hadya, Syria.Milking Awassi ewes (n = 56) were used to test six experimental diets, in which supplements comprised molasses, sugar beet pulp, or cotton seed cake to a traditional control diet contained barley, wheat bran, and barley straw. Milk samples were collected on a weekly basis from April to June.The daily milk production and fat content were enhanced in diets containing urea-treated wheat straw (P < 0.01). The vetch-based diet resulted in a remarkable increase in C6:0, C8:0, C10:0, C12:0, C14:0, and decrease in C18:0 and C20:0 (P < 0.01). An increase in C6:0, C8:0, and C10:0 was also observed in diets containing molasses and sugar beet pulp (P < 0.01). Monounsaturated fatty acids (MUFA) increased by 10% with cotton seed cake-based diets, whereas it decreased by 25% in the vetch-based diet (P < 0.01). Polyunsaturated fatty acids (PUFA) increased in five diets by 10–19%, compared to that of the control group (P < 0.01). This study provides evidence that supplementation using agro-industrial by-product feed stuff influences milk fatty acids profile and therefore enhances potential health benefits.

Review and Analysis of Alternatives for the Valorisation of Agro-Industrial Olive Oil By-Products

By-products and waste from olive production (agriculture) and the olive oil industry (mills and refineries) are an important environmental issue in Mediterranean areas. Industrial waste and by-products contain highly valuable components that can also be phytotoxic. This article reviews recent research on the valorisation of olive by-products under the bioeconomy strategy. The alternatives are classified according to the ‘bioeconomy value pyramid’, which prioritises higher value uses over the current energy and compost valorisation. Special attention is paid to the use of these by-products for animal feed that can be improved by reducing the content of saturated fatty acids (SFAs) and increase the polyunsaturated fatty acids amount considered beneficial in response to their use; this makes the food healthier for humans while simultaneously reducing feeding costs and the environmental impact of livestock.

Effect of olive meal and supplemental enzymes on performance traits, blood biochemistry, humoral immunity response and caecal microbiota of broilers

This study investigated the growth performance, carcass characteristics, blood biochemistry, humoral immunity and caecal microbiota of broiler chicks fed 0, 2, 4, 6, and 8% olive meal (OM) in diet. In addition, this study investigated the use of enzymatic feed supplements (β-glucanase, phytase and hemicellulase) to enhance digestibility of high fibre diets. At the end of the feeding period (42 days), there were no significant differences among dietary groups on broiler growth performance, including bodyweight (BW) and bodyweight gain (BWG), feed intake (FI), and feed conversion efficiency (FCE). The evaluated carcass traits and meat cuts (breast, drumsticks and wings) did not vary among dietary treatments. Although some minor differences were observed in blood albumin and cholesterol concentrations among groups, the cecum microbiota did not differ in broilers. Antibody titers following vaccinations against infectious bronchitis virus (IBV) and Gumboro disease were higher in birds fed 4% OM. Adding supplemental enzymes to diet had minimal effect on the parameters. Findings from this study support the literature, which suggests that OM is a suitable feed by-product in broiler diets. Moreover, including OM in poultry rations has the potential to provide an economic and environmentally friendly alternative to traditional diets. Finally, the current trial identified that the addition of enzymes was not necessary to achieve optimal productive performance in broiler fed diet containing OM. Keywords : Feed by-product, growth, nutrition, poultry

Utilization of H2SO4-hydrolysed phosphorus from herring bone by-products in feed for Atlantic salmon (Salmo salar) 0+postsmolt

Utilization of H₂SO₄-hydrolysed phosphorus from herring bone by-products in feed for Atlantic salmon (<i>Salmo salar</i>) 0⁺postsmolt

Implications of high animal by-product feed inputs in life cycle assessments of farmed Atlantic salmon

Animal by-products may be increasingly relied upon to satisfy nutritional requirements of salmonids and other fed aquaculture species as demand for fish meal outpaces supply. Previous studies of aquaculture supply chains have included either no animal by-product inputs or small inputs of poultry by-products. Australian Atlantic salmon production includes high use of feed inputs derived from poultry and mammalian by-products and provides a case study to explore the environmental implications and methodological challenges associated with these inputs. Life cycle assessment was carried out on a vertically integrated salmon production system in Tasmania, representing approximately 40% of Australian Atlantic salmon production. The system included feed production, smolt/juvenile production, farm grow-out, processing and packaging, and distribution of head-on gutted salmon to market. Impacts from animal production were allocated to by-products on a gross chemical energy basis. Scenario analyses were conducted to determine the extent to which changes in feed conversion ratio, feed composition, and other variables affect results. Sensitivity analysis was carried out on the allocation method for fishery and animal by-products. Environmental impacts associated with Tasmanian salmon fed high quantities of animal by-products were markedly higher than those of previously assessed systems. All impacts were driven by feed production with the exception of eutrophication potential, which was driven equally by feed production and nutrient loss during grow-out. Animal by-products accounted for the majority of all impacts from feed production. Adopting a feed composition without animal by-products would result in dramatic improvements, including a 70% decrease in greenhouse gas emissions. Allocation choice had a clear effect on results, with biophysical allocation methods placing much more burden from animal production on fed systems than economic or no-impact allocation methods. The use of animal by-product inputs in aquaculture feeds has a substantial effect on the environmental profile of farmed salmon products. The magnitude of this effect is dependent on the allocation method chosen for the treatment of products and by-products in upstream systems. The high impact of such systems recognizes the environmental cost of future aquaculture production that may rely more on intensive and high-impact animal production inputs as more efficient fishery inputs become increasingly limited relative to demand.

Palm kernel expeller increases milk fat content when fed to grazing dairy cows

Palm kernel expeller (PKE) is a feed by-product that is used by the dairy and beef industries. This study investigated the effect of partially replacing maize with PKE in a dairy concentrate on milk and ruminal fermentation parameters of Jersey cows grazing kikuyu-ryegrass pasture. Seventy-two multiparous cows were blocked according to milk yield, days in milk, and lactation number and randomly allocated within blocks to one of four treatment concentrates: PKE0, PKE10, PKE20, and PKE30, containing 0, 100, 200, and 300 g PKE/kg dry matter (DM), respectively. Eight rumen-cannulated lactating cows were used in a 4 x 4 Latin square design. All cows grazed pasture as one group, and concentrate was fed at 5.4 kg DM/cow per day. Pasture was allocated at 11.1 kg DM/cow per day. Milk yield was lower with PKE30 than PKE0 (14.3 versus 15.6 kg/cow per day, respectively). Feeding PKE20 and PKE30 was associated with a higher milk fat content of 50.6 and 52.9 g/kg, respectively, than that of 46.3 and 49.3 g/kg of cows fed PKE0 and PKE10, respectively. However, feeding PKE30 compromised fibre degradability. Increased milk fat content and sustained milk yield indicated that 200 g PKE/kg DM can partially replace maize in a dairy concentrate, resulting in a possible added economical advantage, which is dependent on the milk payment system. The lack of a significant effect on milk fat yield and the negative linear relationship of milk protein to milk fat ratio, induced by PKE inclusion, may be unfavourable for certain milk payment systems. Keywords: By-product, fibre-based concentrate, Jersey cow, pasture, ruminal fermentation

Effects of copper oxide bolus administration on productivity and copper and zinc status in grazing beef calves supplemented with dried distillers grains

<h2>ABSTRACT</h2> Corn by-product feed popularity, coupled with their relatively high S content, has prompted researchers to re-examine Cu oxide (CuO) bolus administration. A study was conducted to assess the effects of CuO bolus administration on productivity and Cu and Zn status in grazing beef calves supplemented with dried distillers grains. Calves (n = 74, yr 1; n=54, yr 2) were assigned randomly to 1 of 2 treatments: (1) a single intraruminal CuO (12.5 g) bolus or (2) nonbolus control for a growth trial (141 d, yr 1; 92 d, yr 2). Calves grazed predominantly bermudagrass [<i>Cynodon dactylon</i> (L.)] pastures. Dried distillers grains were offered at a rate of 0.75% of BW (as fed). Calves were weighed at 28-d intervals, and dried distillers grains were adjusted after each weigh day. Blood samples were collected for plasma Cu and Zn concentrations. There was no difference in final BW (<i>P</i> = 0.74, yr 1; <i>P</i> = 0.81, yr 2) or ADG (<i>P</i> = 0.77, yr 1; <i>P</i> = 0.75, yr 2) between bolused and nonbolused calves. Bolus administration did not influence plasma Cu (<i>P</i> = 0.65, yr 1; <i>P</i> = 0.26, yr 2) or Zn (<i>P</i> = 0.55, yr 1; <i>P</i> = 0.73, yr 2) concentrations compared with nonbolused calves. These results suggest that CuO bolus administration was ineffective at altering Cu and Zn status and overall performance in grazing beef calves supplemented dried distillers grains 0.75% (as fed) of BW. Dried distillers grains at 0.75% (as fed) of BW presumably did not create sufficient Cu antagonism.

056 Response of Growing Cattle to a Cumulative Management Strategy Including an Implant, Ionophore, and Byproduct Feed Supplementation While Grazing Tall Fescue Pastures with Varying Toxicity

056 Response of Growing Cattle to a Cumulative Management Strategy Including an Implant, Ionophore, and Byproduct Feed Supplementation While Grazing Tall Fescue Pastures with Varying Toxicity

052 Evaluation of Nitrogen Delivery Methods for Stocker Cattle Grazing Annual Ryegrass

A 2-yr grazing experiment was conducted to evaluate efficacy of nitrogen (N) fertilization, interseeded legumes, and protein supplementation for N delivery to stocker cattle grazing annual ryegrass (Lolium multiflorum). Each year, 90 steers (initial BW, 241 ± 13 kg) were assigned to the following N-delivery methods, with or without monensin fed in a free-choice mineral supplement as a 5 × 2 factorial arrangement of treatments: ryegrass fertilized with 112 kg N/ha (NFERT); ryegrass interseeded with crimson clover (CC, Trifolium incarnatum); ryegrass interseeded with arrowleaf clover (AC, Trifolium vesiculosum); ryegrass plus distillers dried grains with solubles (DDGS) supplemented at 0.65% BW daily; and ryegrass plus whole cottonseed (WCS) supplemented at 0.65% BW daily. Pastures within the interseeded-clover and protein-supplementation treatments were fertilized with 56 kg N/ha at time of establishment. Steers were weighed every 28 d, and forage mass (FM, kg DM/ha) was measured concurrently using the destructive harvest/disk meter double-sampling method. Each of 30 0.81-ha paddocks was stocked initially with 3 "tester" steers, and stocking density (steers/ha) was adjusted using "put-and-take steers" based on changes in FM and steer BW in order to maintain a uniform forage allowance (FA) of 1 kg DM/kg steer BW. Grazing was discontinued on May 11, 2016 in Yr 1 and May 10, 2017 in Yr 2 following 140 and 84 d of grazing, respectively. Data were analyzed as a completely randomized design with repeated measures for which pasture (n = 3) was the experimental unit. Ionophore inclusion did not affect (P > 0.10) any variable measured. Mean FM differed (P < 0.0001) between years and among N-delivery methods (P < 0.10), and mean FA differed (P = 0.005) among N-delivery methods. Steer ADG differed among N-delivery methods (P = 0.02) and between years (P < 0.001), whereas total gain/ha differed (P < 0.0008) among N-delivery methods, but not between years (P = 0.78). Stocking density differed among N-delivery methods (P = 0.02) and between years (P < 0.0001), and grazing-days/ha differed between years (P < 0.0001) and among N-delivery methods (P = 0.001). Results indicate that supplementation with a high-protein by-product feed for cattle grazing annual ryegrass maintained ADG, total gain/ha and grazing-days/ha compared with N-fertilized annual ryegrass, and increased ADG, total gain/ha, and grazing-days over interseeded legumes.

Determination and prediction of digestible and metabolizable energy concentrations in byproduct feed ingredients fed to growing pigs.

ObjectiveAn experiment was conducted to determine digestible energy (DE) and metabolizable energy (ME) of different byproduct feed ingredients fed to growing pigs, and to generate prediction equations for the DE and ME in feed ingredients.MethodsTwelve barrows with an initial mean body weight of 31.8 kg were individually housed in metabolism crates that were equipped with a feeder and a nipple drinker. A 12×10 incomplete Latin square design was employed with 12 dietary treatments, 10 periods, and 12 animals. A basal diet was prepared to mainly contain the corn and soybean meal (SBM). Eleven additional diets were formulated to contain 30% of each test ingredient. All diets contained the same proportion of corn:SBM ratio at 4.14:1. The difference procedure was used to calculate the DE and ME in experimental ingredients. The in vitro dry matter disappearance for each test ingredient was determined.ResultsThe DE and ME values in the SBM sources were greater (p<0.05) than those in other ingredients except high-protein distillers dried grains. However, DE and ME values in tapioca distillers dried grains (TDDG) were the lowest (p<0.05). The most suitable regression equations for the DE and ME concentrations (kcal/kg on the dry matter [DM] basis) in the test ingredients were: DE = 5,528–(156×ash)–(32.4×neutral detergent fiber [NDF]) with root mean square error = 232, R2 = 0.958, and p<0.001; ME = 5,243–(153 ash)–(30.7×NDF) with root mean square error = 277, R2 = 0.936, and p<0.001. All independent variables are in % on the DM basis.ConclusionThe energy concentrations were greater in the SBM sources and were the least in the TDDG. The ash and NDF concentrations can be used to estimate the energy concentrations in the byproducts from oil-extraction and distillation processes.

Animal by-products for feed: characteristics, European regulatory framework, and potential impacts on human and animal health and the environment

1. Alm M., 2012a. Review of the EU feed ban on non-ruminant Processed Animal Proteins: outlook of the European Fat Processors and Renderers Association (EFPRA). TAIEX Workshop, 27th November 2012, Stavropol (Russia) http://www.fefac.eu/ file.pdf?FileID=42256&CacheMode=Fresh. Google Scholar

Distillers By-Product Cattle Diets Enhance Reduced Sulfur Gas Fluxes from Feedlot Soils and Manures.

Total reduced sulfur (TRS) emissions from animal feeding operations are a concern with increased feeding of high-sulfur distillers by-products. Three feeding trials were conducted to evaluate feeding wet distillers grain plus solubles (WDGS) on TRS fluxes. Fresh manure was collected three times during Feeding Trial 1 from cattle fed 0, 20, 40, and 60% WDGS. Fluxes of TRS from 40 and 60% WDGS manures were 3- to 13-fold greater than the 0 and 20% WDGS manures during the first two periods. In the final period, TRS flux from 60% WDGS was 5- to 22-fold greater than other WDGS manures. During Feeding Trial 2, 0 and 40% WDGS diets on four dates were compared in feedlot-scale pens. On two dates, fluxes from mixed manure and soil near the feed bunk were 3.5-fold greater from 40% WDGS pens. After removing animals, soil TRS flux decreased 82% over 19 d but remained 50% greater in 40% WDGS pens, principally from the wetter pen edges (1.9-fold greater than the drier central mound). During two cycles of cattle production in Feeding Trial 3, TRS soil fluxes were 0.3- to 4-fold greater over six dates for pens feeding WDGS compared with dry-rolled corn diet and principally from wetter pen edges. Soil TRS flux correlated with %WDGS, total N, total P, manure pack temperature, and surface temperature. Consistent results among these three trials indicate that TRS fluxes increase by two- to fivefold when cattle were fed greater levels of WDGS, but specific manure management practices may help control TRS fluxes.

A survey of feeding management practices and by-product feed usage on Pennsylvania dairy farms

Dairy industry experts offer many suggestions about ration formulation and feeding management; however, it is unclear what practices are being followed. This study used an electronic survey to gather information about feeding management and the use of by-product feeds in rations from a subset of Pennsylvania dairy farms in 2013. The survey was sent to 200 dairy farms via e-mail, and 41 surveys were completed. All survey responses were based on the month of September 2013. This was not a random sampling. These herds were selected from the Penn State Extension database. Most (97.6%) survey respondents fed a TMR. About half (48.8%) fed one TMR to all lactating cows, and 48.8% fed more than one TMR to lactating cows. More than half (58.5%) of the respondents fed a 60:40 forage-to-concentrate ratio. Distillers grains, brewer’s grains, and yeasts were the most commonly used by-product feeds. Most responding producers analyzed DM in the recommended interval of every other week (biweekly) or once a week (60.9%). Most TMR and forage nutrient testing was done when switching feed types or silos except for by-product commodity feeds, which most producers never tested. Most (75.6%) dairy producers used PC Dart as a management tool. Dairy producers that responded to the survey were successful at feed management, but increasing the amount of nutrient testing on by-product feeds and the use of dairy data analysis tools could improve their success.

Utilization of acid hydrolysed phosphorous from herring bone by-products in feed for Atlantic salmon (Salmo salar) start-feeding fry

The aim of this study was to test the efficacy of a new marine P ingredient from the bone fraction of herring by-products by evaluating the dietary impacts on growth, mineralization and skeletal development in Atlantic salmon fry. Five experimental diets were produced from a fish meal based diet, only differing in the dietary P source and level; low P control (5.5g/kg soluble P), intermediate P (6.5g/kg soluble P) and high P (8.0g/kg soluble P) from either fish bone hydrolysate (FBH1, FBH2) or from NaH2PO4 (NaP1, NaP2). The diets were given for 168days from start of feeding (0.17g fish) until 24weeks of feeding (33g). Weight and specific growth rate did not reveal diet dependent differences except in the initial 10week feeding period where fish fed FBH1 showed lower growth as compared to fish fed the Na–P diets. Mineralization of fish evaluated by whole body and bone ash and mineral contents showed diet dependent differences that were related to dietary P level, but not to P source. Fish fed the low P diet showed clear P deficiency signs with significantly reduced tissue ash and mineral content, reduced whole body Ca:P ratio and morphological deviation from the normal. Histological evaluation of the vertebrae after 19weeks of feeding (15g) revealed stagnation in cartilage development, with accumulation of mature chondrocytes in fish fed low P control and FBH1 diet. FTIR showed that fish fed FBH1 had lower mineralization and increased cross binding in the vertebral end plates. Fish fed FBH2 resembled the positive NaP1 control. Real time qPCR analyses confirmed the histological results, by showing up-regulating of col10a1 (a marker for mature cartilage) in fish fed low P diet and FBH1. Osteocalcin (a marker for mineralization) was also activated in fish fed the low P diet and FBH1, possibly indicating a compensatory regulation in response to inadequate P. The dietary impacts on histology, FTIR and qPCR analyses in the FBH1 fed fish disappeared at 24weeks of feeding (33g). In conclusion, the results showed that P solubilized from bone fraction of herring can be efficiently utilized for growth, mineralization and bone development in Atlantic salmon fry. However, in the initial weeks of feeding, the FBH was a less efficient P source compared to NaP. Overall, the data suggest that P from fish bone hydrolysate is more suited for fish of minimum 15g size. Statement of relevanceThe phosphate (P) rock reserve is a limited resource worldwide. Increased efficiency in the utilization of P and improved recycling of P from waste and manures are examples that could reduce the industry's vulnerability to the limited P supply while also reducing the negative environmental impacts. Recycling of P from fishery offal and development of new available P ingredients to farmed fish will significantly improve the sustainability of the aquaculture industry and reduce the environmental loss. In this paper we show that P hydrolysed from herring bone by-product is as efficient and good for salmon fry as commercially available NaP-salts.