Melhoria da qualidade de filetes de tilápia do Nilo congelados com óleo de alecrim e tomilho

The food industry and the frozen fish sector in particular have benefitted greatly from advancements in food processing technologies. This study investigated the effect of adding natural antioxidants such as rosemary and thyme oil to frozen fillets of Nile tilapia (Oreochromis niloticus) in order to preserve their quality for consumers. Fillets were treated with rosemary and thyme at two concentrations (1% and 1.5%) and then were stored at 4°C. Samples were analyzed over 4 days for bacteriological (aerobic plate count, psychotropic count, and coliform count), chemical (determination of pH, thiobarbituric acid reactive substances-TBARS, and total volatile base nitrogen-TVB-N), and sensory quality examination (color, texture, and odor). Significant differences (P < 0.05) were observed among different groups in terms of aerobic plate count, psychotropic count, and coliform count during the storage. Moreover, pH, TVB-N, and TBARS mean values in the treated groups were lower than those in the untreated group. The best sensory quality was obtained at the highest concentrations (1.5%) of thyme and rosemary oil

The effects of rearing water depths and feed types on the growth performance of African catfish (Clarias gariepinus)

African catfish (Clarias gariepinus) has been growing in popularity as a culture species globally. Although considerable research has been carried out on this species’ feeding preferences, no research has been carried out on optimum water level for growth. This is particularly surprising given this species' benthic nature. This study assessed the effect of different combinations of water levels and types of feed on the growth performance of African catfish. The study employed a 3 × 2 factorial design with three ponds of different water levels (0.5, 1 and 1.5 m) and two types of feeds (floating and sinking). Twelve earthen ponds (1 × 2 m) were each stocked with 16 catfish fingerlings (mean weight ~100 g), and their growth was monitored for 12 weeks. The fish cultured in the shallowest water grew significantly faster than those cultured in the deepest ponds. At the same time, fish cultured in the shallowest ponds had the lowest feed intake rates and consequently the lowest feed conversion ratios. Catfish fed sinking pellets grew faster than those fed floating pellets although the difference was not significant. There was no significant interaction between pond water depth and feed type. The results of this study suggest that the growth and feeding efficiency of C. gariepinus can be optimized by culturing in fairly shallow ponds (0.5 m)

Haematological and biochemical blood profile of African catfish (Clarias gariepinus) cultured in ponds of different water depth and fed sinking versus floating diet

This study contributes data on haematological and biochemical parameters of African catfish, Clarias gariepinus. It employed a 3 × 2 factorial design with three ponds of different water depth (0.5, 1 and 1.5 m) and two types of feed (floating and sinking). Twelve earthen ponds (1 m x 2 m) were stocked with 16 fingerlings catfish each (mean weight ~100g) and their blood parameters were monitored over 12 weeks. Differences in hematological parameters related to water depth were mostly significant, and better results were recorded in fish reared in shallower water ponds. Feed type showed improved hematological parameters with using of sinking diet. Most biochemical parameters showed significant differences in pond waters depth and feed type with better results coincided with rearing fish in shallower water depth and with sinking feed. Conclusively, culturing Catfish in shallow ponds (0.5 m) and use of sinking feed improve physiological response and health condition

Trends in the use of feed and water additives in Egyptian tilapia culture

This study reports the outcomes of a survey on the use of additives in 120 Egyptian grow-out farms carried out between 2018 and 2019. The survey focused on farms rearing Nile tilapia (Oreochromis niloticus) in the biggest tilapia farming region in Egypt (Kafr El-Sheikh). Results were analysed to explore whether any type of additive was used, whether they were feed- or water-based and the frequency of use. A range of farm characteristics and farm management practices were used as independent variables to explain observed additive use patterns reported by farmers. The survey also gathered production data to explore a potential relationship between the use of additives and total marketable yield or mortality. The results of this survey display very low use of any sort of additive in this tilapia farming region (Output Status: Forthcoming/Available Onlin

Modifying the design of pond production systems can improve the health and welfare of farmed Nile tilapia, Oreochromis niloticus

Infected fish have been known to recover from mild illness when they are able to locate to warmer water. This study aimed to replicate this 'behavioural fever' effect in an aquaculture setting by artificially heating a section of a fish pond (thereby introducing a thermal gradient) and effectively modifying pond design. This was achieved through the construction of a 'greenhouse' type structure above a section of the pond. Over the length of the production cycle at three typical Nile tilapia (Oreochromis niloticus) farms, the study collected data on water quality and fish growth and at the end of the cycle, blood samples were taken and total production was recorded. At each farm, fish were divided into two identical ponds, one with a greenhouse covering 3% of the pond surface area and one without. Results showed that greenhouse was effective in warming the surface of the water immediately below it. Oxygen levels were also higher under the greenhouse than outside of it and higher than in the control pond. Fish reared in the greenhouse ponds tended to be larger than the control ponds and had improved physiological and immune status (i.e., better liver and kidney function, higher antioxidant activity and lysozyme count; p < 0.05). The results of this study suggest that low-cost interventions that introduce thermal gradients in aquaculture systems may hold promise for improving health and welfare status of farmed fish in developing countries.Article Information Received 26 September 2022 Revised 05 November 2022 Accepted 28 November 2022; O n l i n e F i r s t A r t i c l

Modifying the design of pond production systems can improve the health and welfare of farmed Nile tilapia, Oreochromis niloticus

Infected fish have been known to recover from mild illness when they are able to locate to warmer water. This study aimed to replicate this 'behavioural fever' effect in an aquaculture setting by artificially heating a section of a fish pond (thereby introducing a thermal gradient) and effectively modifying pond design. This was achieved through the construction of a 'greenhouse' type structure above a section of the pond. Over the length of the production cycle at three typical Nile tilapia (Oreochromis niloticus) farms, the study collected data on water quality and fish growth and at the end of the cycle, blood samples were taken and total production was recorded. At each farm, fish were divided into two identical ponds, one with a greenhouse covering 3% of the pond surface area and one without. Results showed that greenhouse was effective in warming the surface of the water immediately below it. Oxygen levels were also higher under the greenhouse than outside of it and higher than in the control pond. Fish reared in the greenhouse ponds tended to be larger than the control ponds and had improved physiological and immune status (i.e., better liver and kidney function, higher antioxidant activity and lysozyme count; p < 0.05). The results of this study suggest that low-cost interventions that introduce thermal gradients in aquaculture systems may hold promise for improving health and welfare status of farmed fish in developing countries

How feed and water additives are used on Egypt’s Nile tilapia farms

First paragraph: The Egyptian aquaculture industry has seen substantial growth in recent decades and Egypt is now the top producer in Africa. Egypt is also the world’s eighth-largest aquaculture producer, according to the Food and Agriculture Organization of the United Nations (FAO), producing more than 1.6 million tons in 2019, of which the vast majority (66 percent) is Nile tilapia (Oreochromis niloticus)

How feed and water additives are used on Egypt’s Nile tilapia farms

First paragraph: The Egyptian aquaculture industry has seen substantial growth in recent decades and Egypt is now the top producer in Africa. Egypt is also the world’s eighth-largest aquaculture producer, according to the Food and Agriculture Organization of the United Nations (FAO), producing more than 1.6 million tons in 2019, of which the vast majority (66 percent) is Nile tilapia (Oreochromis niloticus).https://www.globalseafood.org/advocate/how-feed-and-water-additives-are-used-on-egypts-nile-tilapia-farms