Physico-chemical and microbiological changes in commercial tilapia (Oreochromis niloticus) during cold storage

[EN] The microbiological and chemical processes are the main responsible for deterioration of fresh fish. Therefore, it is essential to avoid these processes by applying good manufacturing practices during fish handling, distribution and storage. Objective: The aim of this paper was to evaluate the physico-chemical and microbial changes in commercial tilapia (Oreochromis niloticus) during cold storage in order to establish the shelf life since its arrival at the supermarket. Methods: 27 aquacultured tilapia specimens were analyzed at 0, 2, 4, and 7 days of storage at 4ºC. Measurements of texture, color, water holding capacity, total volatile basic nitrogen (TVB-N), thiobarbituric acid index, ATP-related compounds, as well as microbial analyses were carried out. Results: The TVB-N content was high at the beginning of the study, remaining stable during the storage. Lipid oxidation of samples was minimum, so this process did not contribute to the fish spoilage. It was observed the breakdown of inosine-5’- monophosphate (IMP) into Ino (inosine), and Ino into Hx (hypoxantine). The texture parameters and colour underwent changes as a consequence of the fish spoilage. Low microbial counts were observed at day 0, but Enterobacteriaceae and mesophilic counts gradually increased throughout storage. Conclusions: The K1-value showed the progressive spoilage of the fish during the cold storage. The decrease of hardness and firmness confirmed the loss of quality throughout the time of study. The low microbial counts at the beginning of the study demonstrated the good quality of the tilapia; however, the increase of the mesophilic counts at the end of the studied period showed that tilapia was not fit for human consumption at day 7.[ES] Antecedentes: Los procesos microbiológicos y químicos son los principales responsables del deterioro del pescado fresco. Por tanto, es esencial evitar estos procesos aplicando buenas prácticas de fabricación durante la manipulación, distribución y almacenamiento del pescado. Objetivo: El objetivo de este trabajo fue evaluar los cambios físico-químicos y microbiológicos en tilapia comercial (Oreochromis niloticus) durante el almacenamiento refrigerado con el fin de establecer la vida útil desde su llegada al supermercado. Métodos: 27 especímenes de tilapia fueron analizados a día 0, 2, 4 y 7 de almacenamiento a 4 ºC. Se llevaron a cabo medidas de textura, color, capacidad de retención de agua, nitrógeno básico volátil total (N-BVT), índice del ácido tiobarbitúrico, compuestos relacionados con el ATP, así como análisis microbianos. Resultados: El contenido en N-BVT fue alto al principio del estudio, siendo estable durante el almacenamiento. La oxidación lipídica de las muestras fue mínima, por lo que este proceso no contribuyó al deterioro del pescado. Se observó la degradación de inosina-5’- monofosfato (IMP) a Ino (inosina), y de Ino a Hx (hipoxantina). Los parámetros de textura y color sufrieron cambios como consecuencia del deterioro del pescado. Se observaron bajos recuentos microbianos a día 0, pero los recuentos de Enterobacteriaceae y de mesófilos aumentaron gradualmente durante el almacenamiento. Conclusiones: El valor K1 mostró el deterioro progresivo del pescado durante el almacenamiento en refrigeración. La disminución de dureza y firmeza confirmó la pérdida de calidad a lo largo del tiempo de estudio. Los bajos recuentos microbianos al principio del estudio demostraron la buena calidad de la tilapia; sin embargo, el aumento de los recuentos de mesófilos al final del periodo estudiado mostraron que la tilapia no era adecuada para el consumo humado a día 7.Gutiérrez Guzmán, N.; Fernández Segovia, I.; Fuentes López, A.; Ruiz Rico, M.; Barat Baviera, JM. (2015). Physico-chemical and microbiological changes in commercial tilapia (Oreochromis niloticus) during cold storage. Revista Vitae. 22(2):140-147. doi:10.17533/udea.vitae.v22n2a08S14014722

Meat and bone meal as a partial replacement for fish meal in diets for gilthead seabream (Spares aurata): growth, feed efficiency angry amino acid utilization, and economic efficiency

[EN] A trial was conducted to evaluate fish meal (FM) replacement with meat and bone meal (MBM; 53% CP, 15% CL, 27% Ash) in diets for gilthead seabream (Sparus aurata) juveniles. Three extruded experimental diets were formulated (45% CP; 20% CL) to include 0, 50 and 75% of protein from MBM (diets MBM0; MBM50; MBM75). Triplicate groups of seabream (IBW = 25 g) were fed these diets to satiety for 12 weeks. Growth performance and feed efficiency were similar with the diets MBM0 and MBM50, but were lower with diet MBM75, while the opposite was true for feed intake. Whole-body composition was not affected by diets composition except for crude lipid and energy content, which were lower with the diet MBM75. Protein and essential amino acids retention were unaffected by diet composition, while energy retention was lower with the diet MBM75. In terms of economic efficiency, diets with MBM resulted in a lower production costs, with the lowest economic conversion ratio ( kg− 1 fish produced) being obtained for the MBM diets while the maximum economic profit ( kg fish− 1) was obtained for diet MBM50. Overall, up to 50% of FM protein can be replaced by MBM protein in diets for gilthead seabream juveniles, without compromising growth performance, feed utilization, and nutrient retention.Moutinho, S.; Martínez-Llorens, S.; Tomas-Vidal, A.; Jover Cerda, M.; Oliva-Teles, A.; Peres, H. (2017). Meat and bone meal as a partial replacement for fish meal in diets for gilthead seabream (Spares aurata): growth, feed efficiency angry amino acid utilization, and economic efficiency. Aquaculture. 468(1):271-277. doi:10.1016/j.aquaculture.2016.10.024S271277468

A review on broodstock nutrition of marine pelagic spawners: the curious case of the freshwater eels (Anguilla spp.)

To sustain eel aquaculture, development of reproduction in captivity is vital. The aim of this review is to assess our current knowledge on the nutrition of broodstock eels in order to improve the quality of broodstock under farming conditions, drawing information from wild adult eels and other marine pelagic spawners. Freshwater eels spawn marine pelagic eggs with an oil droplet (type II), and with a large perivitelline space. Compared with other marine fish eggs, eel eggs are at the extreme end of the spectrum in terms of egg composition, even within this type II group. Eel eggs contain a large amount of total lipids, and a shortage of neutral lipids has been implied a cause for reduced survival of larvae. Eel eggs have higher ARA but lower EPA and DHA levels than in other fish. Too high levels of ARA negatively affected reproduction in the Japanese eel, although high levels of 18:2n-6 in the eggs of farmed eels were not detrimental. The total free amino acid amount and profile of eel eggs appears much different from other marine pelagic spawners. Nutritional intervention to influence egg composition seems feasible, but responsiveness of farmed eels to induced maturation might also require environmental manipulation. The challenge remains to succeed in raising European eel broodstock with formulated feeds and to enable the procurement of viable eggs and larvae, once adequate protocols for induced maturation have been developed

Arachidonic acid is a Major Component in Gonadal Fatty acids of Tropical Coral Reef fish in the Philippines and Japan

International audienc

Efficient utilization of aquaculture effluents to maximize plant growth, yield, and essential oils composition of Origanum majorana cultivation

Aquaculture effluents are nutrient-rich water containing both inorganic and organic nutrients with a potential to replace chemical fertilizer applications under integrated agricultural systems. A field experiment was conducted to determine the effect of fish effluent as an irrigation water source on the growth, yield, and essential oil composition of sweet marjoram. A randomized complete block design was followed with three irrigation treatments and three replicates i.e. fertigation with chemical fertilizers (control), irrigation with effluents only (effluents), and mixed treatment with 50% effluent and 50% chemical fertilizers (mixed). Marjoram seedlings were transplanted, and two cuts were done at the flowering stage. Samples were analyzed for yield and essential oil. In the first cut, effluents recorded an average of 40.4 cm height and 30.2 branches. It also had significantly higher yields, reaching 12.5ton ha−1 and 2.8ton ha−1 for fresh and dry yields, respectively. For the second cut, mixed had the highest average number of branches (58.8) and average height (59.2 cm). It recorded the highest yields of 26.5ton ha−1 and 10.5ton ha−1 of fresh and dry yields, respectively. Similarly, mixed gave the highest oil content (0.98%), compared to the control (0.84%). Essential oil analysis showed six main constituents; terpinen-4-ol (27.11–32.38%), β-terpineol (9.84–17.22%), γ-terpinene (11.09–15.55%), α-terpinene (6.68–10.34%), sabinene (8.18–9.25%), and cis-sabinene hydrate (5.01–8.64%). The results, therefore, suggest that growing marjoram with a mixed treatment would give the best herbage yields and the highest essential oils with reduced environmental impacts

Hatchery-produced milkfish (Chanos chanos) fry should be fed docosahexaenoic acid-enriched live food: A case of the difficulty in the transfer of improved aquaculture technology in the Philippines

Levels of highly-unsaturated fatty acids, the most important nutritional factors in fry production of marine fish, were compared between hatchery-produced and wild-caught milkfish Chanos chanos fry. The most striking difference found between the fry was in docosahexaenoic acid (DHA: 22:6n-3) levels: DHA levels in hatchery-produced fry were only 37% and 18% of those in wild-caught fry in the polar lipids and neutral lipids, respectively. However, high DHA levels were detected in ovary and spawned eggs from hatchery-reared broodstock. Investigation on the time course change in DHA levels of hatchery-produced fry revealed that the DHA levels of polar lipids drastically declined from 25% at day 0 posthatching to 5% at day 14 posthatching. Nannochloropsis sp. and rotifers Brachionus sp., which were used as live food from day 2 to day 14, did not contain DHA with relatively high eicosapentaenoic acid (EPA: 20:5n-3) levels. DHA level was restored to 13% in 45-day old fry by feeding of formulated diets with a substantial amount of DHA from day 15. Thus, the lack of DHA in the live food appears to lead to the low DHA level in hatchery-produced fry. On the other hand, the cost of DHA enrichment for one milkfish fry was estimated to be 2.6 Philippines centavos, which is equivalent to about 10% of the market price of milkfish fry. The increase of the production cost might not be accepted in domestic hatcheries under competitive marketing with imported fry. Financial and marketing support by the government will be one of the measures to encourage the stable production of domestic milkfish fry with high quality in the Philippines. It is also necessary to conduct institutional campaigns to inform local fry producers and milkfish farmers of the importance of DHA-enrichment

Fatty acid composition of Nile tilapia Orechromis niloticus muscles: A comparative study with commercially important tropical freshwater fish in Philippines

Six tropical freshwater species were collected from Philippines in order to study the characteristic of polyunsaturated fatty acids distributions. 16:0 and 18: l n-9 were the predominant saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) in both neutral lipids (NL) and polar lipids (PL). There was an absence or very low values of n3 highly unsaturated fatty acid (HUFA) in NL of all species. However these fatty acids found in PL of all species studied with higher levels. The high proportions of docosahexaenoic acid (DHA) in PL were found with catfish Arius (20.71%), ayungin (17.64%), and snakehead (17.09%) whereas anabas (4.21%) gave lower DHA content. In PL, arachidonic acids (ARA) was found in high proportions, and also is superior to eicosapentaenoic acid (EPA) (ranged from 3.35 to 10.67% and from 0.42 to 4.74%, respectively). Tilapia lipid appears to be intermediate in nutritional quality between all species studied; the proportions of DHA, EPA and ARA in PL were 16.27%, 4.52% and 9.36%, respectively. According to the n-3/n-6 ratio in both fractions, only ayungin is in the range typical of freshwater fish. Our results indicate that the wild tropical freshwater fish studied here are not good sources of n-3 HUFA fatty acids. Therefore, aquatic nutritionists and farmers should combine their efforts in order to manipulate the nutritional quality of these species to enhance their n-3 HUFAs concentrations especially when these species are reared in captivity system. The wash-out strategy may provide an adequate description of the changes in the fillet lipid fatty acid profiles of fatty fish