• Energy Research

AbstractSoil salinity and freshwater scarcity are among the major global threats to sustainable development owing to their adverse impacts on agricultural productivity especially in arid and semi-arid regions. There is a need to find sustainable alternatives such as salt-tolerant crops and fish to improve people’s livelihoods in marginal areas. This study aimed to maximize the growth and yield of striped catfish (Pangasianodon hypophthalmus) and quinoa (Chenopodium quinoa) cultivated under a biosaline integrated aquaculture–agriculture system. The study was laid in a randomized completely block design of three saline effluent treatments under three replicates: 5000 ppm (T1), 10,000 ppm (T2), 15,000 ppm (T3), and control (T0). Agro-morphological and physiological attributes of quinoa were measured. The crop yield in biomass and mineral element composition was also studied. Additionally, fish growth performance parameters such as feed intake and efficiency, growth, and survival rate were also calculated. Our results indicated that irrigating quinoa with saline aquaculture effluents above 10,000 ppm enhanced the plant growth, yield, and nutrient content of seeds. Furthermore, rearing striped catfish in saline water reaching up to 15,000 ppm did not have adverse impacts on the growth and survival of fish. Overall, integrating catfish and quinoa production under a salinity regime of 10,000 ppm could be a potential solution to ensuring alternative food sources in marginal areas.

AbstractGrowing Nile tilapia in brackish water showed promising results, but the possibility of ammonia exposure can interrupt health status and productivity. Herein, the study tested the combined effects of water salinity and ammonia exposure on the antioxidative status, serum biochemistry, and immunity of Nile tilapia. Fish were assigned to eight groups where fish were reared in saline water (5, 10, and 15 ppt) with continuous or intermittent (every 3 days) total ammonia (TAN) exposure (5 mg TAN/L) (2 × 4 factorial design). After 30 days, the water salinity, TAN, and their interaction were markedly (P < 0.05), affecting the growth performance (final weight, weight gain, and specific growth rate) and survival rate of Nile tilapia. The growth performance and survival rate were markedly lower in tilapia grown in 15 ppt with continuous TAN exposure than in the remaining groups. The results showed that fish exposed to higher salinity levels (10 and 15 ppt) and continuous TAN exposure had a more robust antioxidative response, as evidenced by higher superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities and lower malondialdehyde (MDA) levels in the homogenates of the gills, intestines, and livers. The gills were notably affected, with congestion of primary filaments blood vessels and degeneration or shedding of secondary filaments epithelium, especially at salinity levels of 10 and 15 ppt. Additionally, the intestines displayed hyperplasia and inflammatory cell infiltration of intestinal mucosa at 5–10 ppt salinity, degeneration and sloughing of the intestinal epithelium at 15 ppt saline water, and increased goblet cell number at salinity of 10 ppt. The study found that continuous TAN exposure had a more significant impact on the fish, especially at higher salinity levels. Water salinity, TAN, and their interaction significantly affected all measured blood bio-indicators (total, albumin, globulin, ALT, AST, creatinine, urea, glucose, and cortisol levels). The phagocytic activity and index were markedly lowered in fish reared in 15 ppt with continuous TAN exposure, while the lysozyme activity was decreased in fish grown in 5, 10, and 15 ppt with continuous TAN exposure. In conclusion, Nile tilapia showed the possibility of growth with normal health status in brackish water (5–10 ppt); however, continuous TAN exposure can impair the productivity of tilapia, especially with high salinity (15 ppt).

The increasing global population has led to an increase in food demand; consequently, aquaculture is one of the food production sectors that has offered opportunities to alleviate hunger, malnutrition, and poverty. However, the development of a sustainable aquaculture industry has been hindered by the limited availability of natural resources as well as its negative impact on the surrounding environment. Hence, there is an urgent need to search for better aquacultural production systems that, despite their high productivity and profitability, utilize fewer resources such as water, energy, land, and capital in conjunction with a negligible impact on the environment. Biofloc technology (BFT) is one of the most exciting and promising sustainable aquaculture systems; it takes into account the intensive culture of aquatic species, zero water exchange, and improved water quality as a result of beneficial microbial biomass activity, which, at the same time, can be utilized as a nutritious aquaculture feed, thus lowering the costs of production. Furthermore, BFT permits the installation of integrated multi-trophic aquaculture (IMTA) systems in which the wastes of one organism are utilized as feed by another organism, without a detrimental effect on co-cultured species. This review, therefore, highlights the basics of BFT, factors associated with BFT for the successful production of aquatic species, the significance of this food production system for the sustainable production of economically important aquatic species, its economic aspects, drawbacks, limitations, and recommended management aspects for sustainable aquaculture.

AbstractThis study investigated the utilization of fish effluents as irrigation water and nutrient sources to close the crop yield gap and increase Swiss chard productivity in a closed-loop sandponics system. The experiment was operated using desalinated water from a Reverse Osmosis plant. The study followed a completely randomized design with four variants, i.e., an aquaponic system (T1) and three sandponics systems; October (T2), Benu Suef (T3) and Fayoum (T4). Results indicated that T2 and T4 significantly recorded the highest plant heights in all cuts. The number of leaves per plant decreased with the increase in cut number. Leaf area and chlorophyll was significantly different between the treatments. T1 significantly had low biomass yields in cuts one and two, almost 40% less than T3 and T4. The various systems efficiently minimized water consumption ranging from 1.5 to 1.96 L/m2/day. The crop protein content ranged from 11.84 to 18.72 mg/100 g dry weight. Mineral composition in cut one was significantly higher compared to cuts two and three. The study recommends a novel technique for increasing crop production using fish effluents under sandponics systems while increasing water and fertilizer efficiency to close the crop yield gap.

As the world population increases, there will be an increase in demand for poultry meat. To satisfy this requirement, sustainably will be a significant challenge as different countries in the world face different health problems. Additionally, for decades, poultry nutritionists have worked on sustainability in broiler manufacturing plants. The usage of short- and medium-chain fatty acids (MCFAs), which have positive effects as growth promoters and immunostimulants, is a pioneering way to decrease the cost of diets and improve environmentally friendly and sustainable production in this critical era. This study aimed at evaluating the influences of alpha-monoglyceride (alpha-monolaurin) on the growth performance, biochemical parameters, lipid profiles, liver oxidative stress, and immune response in broilers. Alpha-monolaurin was included at the levels of 0 (control), 0.25, 0.5, and 1 g/kg in broiler diets. After 33 days, dietary supplementation of alpha-monolaurin showed no impact on the feed intake; however, broilers fed 0.5 g/kg feed displayed a significantly reduced food conversion ratio, as compared to the control (p ≤ 0.05). However, body weight and body weight gain tended to increase after 0.25 g/kg alpha-monolaurin supplementation, as compared to other groups. The highest European production efficiency factor (EPEF) was obtained with 0.25 g/kg alpha-monolaurin supplementation. The ether extract utilization and spleen weight were improved substantially (p ≤ 0.05) by alpha-monolaurin supplementation, but muscle and other organ weights were not affected. Plasma alanine transaminase (ALT) was decreased significantly by alpha-monolaurin supplementation, while plasma total protein and albumin were enhanced (p ≤ 0.05). Interestingly, broilers fed alpha-monolaurin displayed an increased antibody titer of the Newcastle disease (ND) virus and muscle unsaturated fatty acid content, and a decreased liver content of malondialdehyde (MDA). It could be assumed that dietary supplementation of alpha-monolaurin positively impacts birds’ feed efficiency and immune response and can be applied as a natural immune enhancer in the broiler industry.