An NMR-based metabolomic assessment of cultured cobia health in response to dietary manipulation

Commercial aquaculture feeds rely heavily on fishmeal and fish oil, which can be expensive and ecologically unsustainable. To evaluate the efficacy of reduced fishmeal diets for outgrowth, a dietary study was conducted on the finfish cobia, Rachycentron canadum. NMR-based metabolomic techniques were used to assess the effect of decreasing dietary fishmeal on the health of the cobia. Filtered serum ¹H NMR spectra analysed by principal components analysis (PCA) showed cobia fed reduced fishmeal diets were metabolically different than cobia on control diets. In particular, tyrosine and betaine increased in cobia fed reduced fishmeal diets while glucose decreased, suggesting that these cobia were not receiving the necessary nutritional components required for energy and growth. The formulated control diet contributed to enriched growth and significantly elevated lactate levels suggesting enhanced gut microflora metabolism in response to dietary components. The results show that NMR-based metabolomic analysis is a useful tool in aquaculture studies.     

改进测定鱼粉中挥发性盐基氮方法的探讨

本文采用碳酸钾溶液作碱性试剂,并用自动凯氏定氮仪测定鱼粉中的挥发性盐基氮,与国标GB/T5009.44-1996中半微量定氮法比较,两种方法无显著性差异,测定结果令人满意。该方法快速、准确。     

Production and refinement of oil from carp (Cyprinus carpio) viscera

Carp viscera oil can be obtained by both ensilage and fishmeal processes. This study examined the refinement of carp (Cyprinus carpio) oils obtained by both processes, and compared crude, neutralised, bleached, winterised and deodorised oils’ characteristics and lipid profiles. Refined oils obtained by the two processes did not present significant difference (p > 0.05) for Lovibond colour, free fatty acids, and thiobarbituric acid values. The major fatty acids identified in the carp crude, bleached and refined oils were oleic, palmitic, palmitoleic, linoleic and linolenic, constituting approximately 69.6% of the total fatty acids of the oils. The n − 3/n − 6 ratio was approximately 1.05 for refined oil. Therefore, carp viscera refined oil can be considered a rich source of essential fatty acids of the n − 3 and n − 6 series.     

原子吸收光谱法测定鱼粉中铬含量测量结果的不确定度分析

依据GB/T13088-2006《饲料中铬的测定》标准测量鱼粉中的铬含量,对整个测量过程中不确定度的来源进行了分析,并对不确定度各个分量进行了评定、合成,最后得出合成不确定度和有效自由度。     

Fishmeal-based diet decreases the redness of sunshine bass (Morone chrysops × Morone saxatilis) fillets

The objectives of the present study were to determine the effects of feeding a fishmeal-based diet on color attributes and lipid oxidation in sunshine bass (Morone chrysops × Morone saxatilis) fillets during retail display. A balanced diet containing 30 percent fishmeal (FM) or a diet containing poultry byproduct meal as a complete replacement of fishmeal (PB) was fed to sunshine bass for fifteen months. Harvested fish were filleted, overwrapped with polyvinyl chloride film and stored at 2 °C (REF) or over ice (ICE), under an illuminated retail display. Samples (n = 6) were analyzed after 0, 3, 6, or 9 d storage for color attributes (CIE L^∗, a^∗, b^∗, hue angle and chroma), thiobarbituric acid-reactive substances (TBARS), and pH. TBARS and pH increased (P < 0.05) during storage, indicating progress in lipid oxidation and protein changes. FM fillets demonstrated lower (P < 0.05) a^∗ (redness) value and greater (P < 0.05) hue angle than PB fillets. Since consumer acceptance of sunshine bass is dependant upon its white flesh, fishmeal supplementation could be used as a dietary strategy to improve fish marketability.     

Differentiation of meat and bone meal from fishmeal by near-infrared spectroscopy: Extension of scope to defatted samples

Current and future legislation regarding the use of processed animal proteins in animal nutrition requires the availability of robust analytical methods that allow for proper implementation of corresponding legal restrictions. Near-infrared microscopy (NIRM) is a spectroscopic method that allows for the differentiation between meat and bone meal and fishmeal and it is assumed that the different content and composition of the fat is one of the factors responsible for the observed differences. Here a study of the NIRM method has been conducted in order to check for the influence of intentionally introduced reduction of the fat content on the capability of the NIRM method to correctly classify defatted samples. This has practical implications, since processed animal proteins may be defatted by solvents under real world conditions. The results confirmed that the scope of the NIRM method could be successfully extended to samples that have been previously extracted with nonpolar solvents. Only after the use of stricter techniques such as extraction with chlorinated solvents or hydrolysis the NIRM method produced a higher portion of wrong classifications. However, since these extraction techniques are not often used under real world conditions, the impact upon the use of the NIRM method in the feed sector for the specific application of the differentiation between meat and bone meal and fishmeal is minor.     

N‐3 enrichment of pork with fishmeal: Effects on production and consumer acceptability

This study aimed to develop pork products of acceptable organoleptic quality enriched with long‐chain n‐3 polyunsaturated fatty acids (LC n‐3 PUFA). Female pigs were fed a finisher diet containing 15% PorcOmega? tuna fishmeal or a commercial diet. Pigs and rations were weighed weekly. The feed conversion ratio was significantly lower in pigs fed fishmeal than in controls (2.61 ± 0.01 versus 2.96 ± 0.06, p <0.05). After 6 weeks, the pigs were butchered and the fatty acid contents of selected pork products were analyzed by gas chromatography. Shelf life was tested by thiobarbituric acid‐reactive substances (TBARS), initially and after 5 days of cold storage, and sensory qualities were evaluated after cooking. LC n‐3 PUFA contents of pork products from pigs fed fishmeal were higher than in controls (steak 300%, stir‐fry 250%, diced 520%, mince 480%, sausage 360%; p <0.05 in all cases). There were no differences between n‐3‐enriched and regular pork in either TBARS content of stored raw products or sensory characteristics after cooking. Incorporating fishmeal in the finisher diet resulted in greater feed efficiency and production of nutritionally enhanced pork products with organoleptic profiles and stability comparable to those of regular pork.     

采用近红外光谱法测定鱼粉的品质

本文比较了用近红外漫反射光谱(NIRS)定量测定和用传统化学方法测定鱼粉中的蛋白质、脂肪和水分含量,结果发现,用近红外漫反射光谱(NIRS)定量测定鱼粉的品质有良好的效果,完全可以替代传统的化学方法。该方法快速、准确且无药品试剂污染,其重现性优于传统化学法。