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The omega‐3 long‐chain polyunsaturated fatty acids (n‐3 LC‐PUFA), such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are essential fatty acids for marine fish. This study aimed to evaluate different dietary n‐3 LC‐PUFA on the growth, intestinal health and microbiome in carnivorous marine fish Trachinotus ovatus. Three diets, respectively, supplemented with fish oil, EPA‐enriched oil and DHA‐enriched oil were fed juvenile T. ovatus for 10 weeks. The results showed that the three groups showed no difference in the growth, histology and digestive enzyme activities of anterior intestine. Moreover, the intestinal ACP and ALP activities and tnfɑ mRNA level were increased in the EPA‐enriched group, whereas the serum diamine oxidase activity and intestinal lysozyme activity and malondialdehyde content were decreased in both EPA‐ and DHA‐enriched groups. Meanwhile, these two diets also down‐regulated the mRNA expression of Mucin 2, Mucin 13, hes1‐b, Krueppel‐like factor 4 and Occludin, and up‐regulated the zonula occludens‐1 mRNA levels in intestine. Moreover, the two groups significantly decreased the intestinal Vibrio abundance and increased the probiotic proportions, especially in the EPA‐enriched group. These results indicate dietary n‐3 LC‐PUFA would facilitate normal intestinal function and probiotics profiles of T. ovatus, and the EPA‐enriched group appears to be more positive. [ABSTRACT FROM AUTHOR]

The effects of a commercial probiotic (Clostridium butyricum) on growth, gut microbiota, digestion‐related enzyme activity, antioxidant capacity and water quality in genetically improved, farmed tilapia (GIFT; Oreochromis niloticus) were assessed in a closed‐circuit, container culture system. A basal diet containing commercially available C. butyricum at 3.0 × 1010, 1.5 × 1011 and 3.0 × 1011 CFU/kg, and a control diet were fed to tilapia fries for 90 days. Growth performances and water quality were improved by probiotic treatment. Activities of digestive enzymes (amylase, lipase and trypsin) were improved, especially with 1.5 × 1011 CFU/kg (p < 0.05). After feeding for 45 days and 90 days, antioxidant capacity in the liver, spleen and head kidney, and the plasma immunity in the treatment groups improved. The analysis of 16S rRNA indicated that C. butyricum did not significantly increase its abundance in the hindgut, but could modulate gut microbial communities and significantly increase functions relating to nitrogen metabolism, phosphorylation and proteinases. These results support the administration of C. butyricum, especially at 1.5 × 1011 CFU/kg. As a probiotic for high‐density tilapia, C. butyricum improves water quality, growth performance, antioxidant capacity and the immune response of GIFT under crowding stress. [ABSTRACT FROM AUTHOR]

The effects of N‐carbamylglutamate (NCG) on growth, intestinal enzyme activities, immunological and antioxidant parameters were evaluated by a 56‐d feeding trial in Pelteobagrus fulvidraco fed diets containing NCG with 0, 250, 500, 1,000 or 2,000 mg/kg, respectively. The results showed that 250 mg/kg of NCG resulted in significantly higher weight gain, intestine fold height, intestine lipase, serum lysozyme, glutathione peroxidase and total antioxidant capacity than control (p < 0.05). However, higher intestine trypsin, arginase, arginine decarboxylase, ornithine decarboxylase, diamine oxidase activities and serum nitric oxide content were observed in 500 mg/kg NCG group compared to control or 2,000 mg/kg (p < 0.05). The survival rate, intestine muscular layer thickness, serum lysozyme and superoxide dismutase activities in 2,000 mg/kg NCG group were significantly lower than those in control and 250 mg/kg group, accompanied by the higher feed conversion ratio in the same group (p < 0.05). Together, dietary NCG level at 250 or 500 mg/kg improved growth, intestinal enzyme activities, immunological and antioxidant abilities, while high NCG level of 2,000 mg/kg had a negative effect. Quadratic regression analysis on weigh growth, diamine oxidase and lysozyme activities indicated that the recommended optimum dietary NCG level was 213.48–314.50 mg/kg of the dry diet. [ABSTRACT FROM AUTHOR]

The aim of the present work was to evaluate the effects of copper (Cu) and cadmium (Cd) on the physiology of the red macroalga Porphyra haitanensis Chang and Zheng. The alga was cultured in media with different Cu or Cd concentrations for 7 days. The relative growth rate was significantly reduced at Cu concentrations of 0.10 mg l−1 and above or at Cd concentrations of 4 mg l−1 and above. Chlorophyll a (Chl a), carotenoids (Car), phycoerythrin (PE) and phycocyanin (PC) contents decreased at high Cu or Cd concentrations, and PE content increased at 0.10 mg l−1 Cu or 4-8 mg l−1 Cd. Moreover, the optimal quantum yield, maximum net photosynthetic rate (Pm) and apparent photosynthetic efficiency (α) were significantly reduced at high Cu or Cd concentrations. In contrast, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity increased in response to Cu or Cd treatment. Catalase activity increased at 2-8 mg l−1 Cd and significantly declined at 0.50 mg l−1 Cu or 10 mg l−1 Cd. Nitrate reductase (NR) activity declined at high Cu or Cd concentrations. Consequently, both Cu and Cd were physiological stressors for P. haitanensis, with Cu being more toxic than Cd. This work has generated valuable knowledge about the toxic effects of Cu and Cd on macroalgae. [ABSTRACT FROM AUTHOR]

The effects of nucleotides on growth, and physiological and antioxidant parameters were evaluated by feeding Pelteobagrus fulvidraco diets supplemented with 0, 0.2, 0.4, 0.6, 1.0 or 1.5 g kg−1 of nucleotides respectively. All nucleotide groups showed higher specific growth rate, feed efficiency, protein efficiency ratio, whole-body lipid content and serum cholesterol concentrations than the control group, but the significant difference was seen only between fish from the 1.5 g kg−1 nucleotide group and fish from the control group. Whole-body ash content in fish from the 0.6 g kg−1 nucleotide group, and liver superoxide dismutase and catalase in fish from the 0.4 g kg−1 nucleotide group were significantly higher than those in fish from the control group. Respiratory burst activity was significantly higher in fish from the 0.6, 1.0 and 1.5 g kg−1 nucleotide groups than in fish from the control. This finding was accompanied by lower liver concentrations of thiobarbituric acid-reacting substances in fish from the same groups compared to those from the control group. The results indicate that dietary nucleotides could improve growth and antioxidant responses in juvenile yellow catfish. [ABSTRACT FROM AUTHOR]

Marine coastal ecosystems are suffering from metal pollution such as mercury. Hizikia fusiformis is a commercially important brown marine macroalga. Entire thalli of H. fusiformis were cultured in media with different mercury concentrations for 7 days to examine the physiological effects of mercury exposure on this species. The relative growth rate of H. fusiformis was significantly reduced at 0.04 mg l-1 mercury. Chlorophyll a and carotenoid contents were not affected by mercury concentrations ≤0.10 mg l-1, but significantly decreased at 0.20 and 0.40 mg l-1. Optimal quantum yield, maximum net photosynthetic rate, and apparent photosynthetic efficiency were reduced with increasing mercury concentrations. Malondialdehyde contents were significantly increased at 0.04-0.40 mg l-1 mercury. Superoxide dismutase activity increased at 0.02-0.10 mg l-1 mercury. Both superoxide dismutase and catalase activity strongly decreased at 0.20 and 0.40 mg l-1. Nitrate reductase activity declined at mercury concentrations ≥0.04 mg l-1. Consequently, the results suggest that H. fusiformis could tolerate mercury stress at very low concentrations but that mercury at high concentrations has toxic effects on H. fusiformis through its negative influence on photosynthesis and related physiology. The results also illuminate the physiological response mechanisms of algae to mercury exposure. [ABSTRACT FROM AUTHOR]

Simple Summary: The black soldier fly Hermetia illucens is a potentially promising feed or food source due to its valuable nutritional composition. However, its fat content and fatty acid composition significantly vary with the rearing substrates, making it a flexible resource in fat quantity and quality. Recent research has attempted to manipulate the fat content and fatty acid composition of the insect with modulated feed formulation. Nevertheless, the results of most investigations are not comparable, since the rearing substrates used are various organic wastes with complex substrates. Therefore, it is necessary to perform a quantitative and accurate assessment of dietary fat on larval yield and fatty acid composition. In this study, the influence of two supplemental levels of six dietary fat sources on growth and nutrient composition was evaluated, especially fatty acid composition of black solider fly Hermetia illucens larvae. Additionally, the relationships between dietary fat and larval growth and fatty acid composition were quantitatively determined. Our work deepens the understanding of the fat/fatty acid needs of this insect and therefore enlightens the purposive culture of insects for appropriate fat supply. A 16-day rearing trial was performed to investigate the influence of two supplemental levels (5% and 10%) of six dietary fat sources (linseed oil, peanut oil, coconut oil, soybean oil, lard oil and fish oil) on the growth, development and nutrient composition of black solider fly larvae. Our results demonstrated that the pre-pupa rate of larvae was linearly influenced by dietary C18:0, C18:3n-3 and C18:2n-6 content (pre-pupa rate = 0.927 × C18:0 content + 0.301 × C18:3n-3 content-0.258 × C18:2n-6 content p < 0.001)), while final body weight was linearly influenced by that of C16:0 (final body weight = 0.758 × C16:0 content, p = 0.004). Larval nutrient composition was significantly affected by dietary fat sources and levels, with crude protein, fat and ash content of larvae varying between 52.0 and 57.5, 15.0 and 23.8, and 5.6 and 7.2% dry matter. A higher level of C12:0 (17.4–28.5%), C14:0 (3.9–8.0%) and C16:1n-9 (1.3–4.3%) was determined in larvae fed the diets containing little of them. In comparison, C16:0, C18:1n-9, C18:2n-6 and C18:3n-3 proportions in larvae were linearly related with those in diets, with the slope of the linear equations varying from 0.39 to 0.60. It can be concluded that sufficient C16:0, C18:0 and C18:3n-3 supply is beneficial for larvae growth. Larvae could produce and retain C12:0, C14:0, and C16:1n-9 in vivo, but C16:0, C18:1n-9, C18:2n-6 and C18:3n-3 could only be partly incorporated from diets and the process may be enhanced by a higher amount of dietary fat. Based on the above observation, an accurately calculated amount of black soldier fly larvae could be formulated into aquafeed as the main source of saturated fatty acids and partial source of mono-unsaturated and poly-unsaturated fatty acids to save fish oil. [ABSTRACT FROM AUTHOR]

• Integrated morphological, physiological and omics analyses were performed to uncover the mechanism of oAANAT in switchgrass. • oAANAT plays pivotal roles in plant growth and flowering. • oAANAT is a positive regulator involved in photosynthesis. • Overexpression of oAANAT in switchgrass increases defence capacity. Arylalkylamine N -acetyltransferase (AANAT) catalyses the acetylation of serotonin, a rate-limiting process in melatonin biosynthesis. To obtain better insight into the underlying mechanism of AANAT's actions in switchgrass growth, flowering and defence, we performed integrated morphological, physiological and omics analyses between overexpressed oAANAT transgenic lines in wild-type and transgenic control (expressing only the empty vector) plants. We showed that oAANAT played pivotal roles in modulating plant growth through its regulation of cell elongation, and regulating flowering through photoperiod and GA pathways. In relation to photosynthesis, oAANAT promoted photosynthetic efficiency primarily through regulating leaf anatomical structures, stomatal development and chlorophyll metabolism. Moreover, oAANAT overexpression can trigger a number of defence responses or strategies, including antioxidant enzymatic properties, non-enzymatic capacity, significantly activated phenylpropanoid biosynthesis, and adaptive morphological characteristics. This study unveils the possible molecular mechanisms underlying oAANAT dependent melatonin functions in switchgrass, providing an important starting point for further analyses. [ABSTRACT FROM AUTHOR]