Response to the ration levels on growth,body composition,energy, and protein maintenance requirement of the Indian catfish (<Emphasis Type="Italic">Heteropneustes fossilis</Emphasis>—Bloch 1974)

An 8-week growth study was conducted to determine the effect of ration level, energy, and protein maintenance requirement of catfish, Heteropneustes fossilis–Bloch, fingerling (7.90 ± 0.55 cm; 3.10 ± 0.28 g) by feeding casein–gelatin-based purified diet (40% CP; 3.61 kcal g-1 GE) at six ration levels 1–6% of BW/day, at 0800 and 1700 h, in triplicate, with 20 fish per trough fitted with water flow-through system of volume 55 L. Maximum live weight gain, best feed conversion ratio (FCR), best specific growth rate (SGR), and highest protein efficiency ratio (PER) were evident for ration levels of 4–5% body weight. However, second-degree polynomial regression analysis for weight gain, FCR, PER, protein, and energy retention data indicated that the break-points occurred at 5.08, 4.18, 4.05, 4.16, and 4.17% BW/day, respectively. Significantly (P < 0.05) higher body protein content was recorded at 4 and 5% rations. While a linear increase in body fat content with inverse relationship in moisture content was evident with increasing rations. Ash content remained insignificantly (P > 0.05) low at higher rations. Protein and energy retention values also produced significant (P < 0.05) differences. Based on the results obtained, it is recommended that feeding in the range of 4 to 4.5% BW/day, corresponding to 1.60–1.80 g protein and 14.46–16.27 kcal energy g100 g⁻¹ of the diet/day is optimum for the growth and efficient feed utilization of H. fossilis, while 2–3% ration levels (0.80–1.20 g protein and 7.23–10.84 kcal energy) suggest that these amounts approximate to the maintenance requirement of this fish.     

Review of infectious agent occurrence in wild salmonids in British Columbia,Canada

Wild Pacific salmonids (WPS) are economically and culturally important to the Pacific North region. Most recently, some populations of WPS have been in decline. Of hypothesized factors contributing to the decline, infectious agents have been postulated to increase the risk of mortality in Pacific salmon. We present a literature review of both published journal and unpublished data to describe the distribution of infectious agents reported in wild Pacific salmonid populations in British Columbia (BC), Canada. We targeted 10 infectious agents, considered to potentially cause severe economic losses in Atlantic salmon or be of conservation concern for wild salmon in BC. The findings indicated a low frequency of infectious hematopoietic necrosis virus, piscine orthoreovirus, viral haemorrhagic septicaemia virus, Aeromonas salmonicida, Renibacterium salmoninarum, Piscirickettsia salmonis and other Rickettsia-like organisms, Yersinia ruckeri, Tenacibaculum maritimum and Moritella viscosa. No positive results were reported for infestations with Paramoeba perurans in peer-reviewed papers and the DFO Fish Pathology Program database. This review synthesizes existing information, as well as gaps therein, that can support the design and implementation of a long-term surveillance programme of infectious agents in wild salmonids in BC.     

Partial replacement of dietary soybean meal by high‐protein distiller's dried grains (HPDDG) supplemented with protease enzyme for European seabass,Dicentrarchus labrax fingerlings

High‐protein distillers dried grains (HPDDG) is a co‐product of ethanol production that uses prefractionation technology. A 70‐day growth trial was conducted to investigate the effect of partial replacement of dietary soybean meal by high‐protein distiller's dried grains (HPDDG) with protease enzyme supplementation (PROXYM ULTRA^®) on growth performance, physiological parameters and histological changes of the intestine of European sea bass, Dicentrarchus labrax fingerlings. The results indicated that increased dietary HPDDG levels up to 50% of HPDDG supplemented with protease significantly increases growth performance and feed utilization and improved FCR of sea bass. In addition, replacement of SBM by HPDDG supplemented with protease enhanced feed intake efficiency and the health status of fish. Haematology and serum biochemistry (haemoglobin (Hb)), red blood cells (RBCs), white blood cells (WBCs) and humeral immune parameters including total protein, globulin, cholesterol, lysozyme activity and total antioxidant capacity significantly increased with increase in HPDDG supplemented with protease in the diets. Results of this study indicated that HPDDG supplemented with protease is a good alternative protein source for aquaculture feed and can be included up to 50% as a replacement of SBM without compromising growth performance and physiological parameters of sea bass.     

Possible effect of lesser galangal (Alpinia officinarum) extracts encapsulated into mesoporous silica nanoparticles on the immune status of rainbow trout (Oncorhynchus n)

Using plant extracts as immunostimulants in aquaculture has prove effectiv in resisting infectious disease, in addition to being safe and inexpensive. The present study is concerned about the prospective mode of action of using lesser galangal extract (Alpinia officinarum) encapsulated into amine surface functionalized mesoporous silica nanoparticles (MSN) in order to elevate the immune status of rainbow trout (Oncorhynchus mykiss). Fish were randomly divided into 6 groups and fed for 4 weeks with commercial diets supplemented with 0% (control), 0.5% and 1.5% of lesser galangal extract, and with previous concentrations encapsulated with MSN (0.5% + MSN, 1.5% + MSN) and MSN (without extract). The effects of the feeding trial on the innate humoural immune parameters (total protein, myeloperoxidase content, lysozyme antiproteases and bactericidal activities) in rainbow trout were examined. Also, the influence of dietary supplement on some immune‐related genes in rainbow trout head kidney (TNF, IL‐8, IL‐1b, LYZ2 and CD4) after challenge with Yersinia ruckeri was examined. The results revealed enhancement in immune parameters in all treatment groups compared to the control, especially in the fish group fed with 1.5% + MSN which showed the highest significant difference (p < .05) in total protein, lysozyme and antiproteases activities. Also, feeding lesser galangal extract encapsulated into MSN led to an increase in myeloperoxidase content and bactericidal activity. An improvement in the expression of immune‐related genes has been recorded in fish groups fed doses of lesser galangal extract and lesser galangal extract encapsulated into MSN compared to the control or to the group fed with MSN only. Particularly, the group fed with 0.5% + MSN showed a significant up‐regulation in most of the immune‐related genes. The current investigation supports using lesser galangal extract encapsulated into MSN in fish diets as a supplement to enhance the immune response of rainbow trout and elevate its resistance to infectious diseases.     

Comparison of growth,digestive system maturation and skeletal development in sea bass larvae reared in an intensive or a mesocosm system

The quality of development in intensive or mesocosm hatchery‐reared Dicentrarchus labrax larvae was investigated using physiological indicators assessing ontogeny. Larvae were reared in intensive (120 L tanks) and in mesocosm systems (20 m³ enclosures) with the same feeding sequence, excluding the wild zooplankton naturally available in mesocosms. Faster growth was recorded since early development [16 day after hatching (DAH)] in the mesocosm. Maturation of the digestive system also occurred earlier as indicated by the higher amylase secretion ratios, the intestinal maturation index (alkaline phosphatase/leucine–alanine peptidase and aminopeptidase‐N/leucine–alanine peptidase ratios) and the more developed intestinal epithelium at 23 DAH. Nevertheless, the delay in digestive maturation in the intensive system seemed retrieved within few days. In both the groups, the number of vertebrae ranged between 24 and 26, with the dominant class being 25 vertebrae. However, the distributions differed between treatments for meristic characteristics, ossification stages and incidence of malformation types. Loss of a vertebra was more frequent in the intensive system, while the appearance of an additional vertebra was more frequent in the mesocosm. Ossification at 37 DAH was also more advanced in the mesocosm in addition to a lesser rate and severity of skeletal malformations. It is suggested that the early nutritional contribution of mesocosm wild zooplankton, yet at densities of 0.2–0.7 prey mL^?1, had key effects on larvae development since the early stages.     

Physico-Chemical Profiling of Promising Sweet Orange Cultivars Grown Under Different Agro-Climatic Conditions of Pakistan

Sweet oranges are produced on large scale all over the world and demanded due to less number of seeds and are better juice quality. A study was carried out with the objective to characterize promising sweet orange cultivars for better quality fruits production under different agro-climatic conditions of Punjab (Pakistan). Fruits of three promising sweet orange (Citrus sinensis L. Osbeck) cultivars viz. ‘Blood Red’, ‘Musambi’ and were harvested from commercial citrus groves at five different locations. Starting from Multan, in the direction of increasing altitude, four more sites viz. Sahiwal, Faisalabad, Sargodha and Chakwal were selected after every 100–150?km distance. Fruits were evaluated in terms of different physical and biochemical characters. Results showed significant influence of climatic conditions on physico-chemical properties of the cultivars at all the locations. Fruits harvested from Multan and Sahiwal showed higher fruit weight, diameter and peel weight. More juicy fruits with higher vitamin C content were produced under mild temperature environmental conditions of Chakwal. Overall, ‘Musambi’ fruits had more total soluble solids and reducing and total sugars. ‘Musambi’ was found to be good source of bioactive compounds i.?e. vitamin C and total phenolic content, had the maximum antioxidant activity as compared to ‘Blood Red’ and ‘Succari’ and may be explored as potential cultivar in Sargodha and Chakwal.     

Biodiversity in Indigenous Germplasm of <Emphasis Type="Italic">Pyrus </Emphasis>from Pakistan Based on Phenotypical and Morphological Traits

A comprehensive analysis of various horticulturally important morphological traits of sixty pear accessions located in five districts of Azad Jammu and Kashmir (Pakistan) was carried out. Several qualitative and quantitative traits were investigated in situ and after the harvesting of leaf and fruit samples. The rich diversity was observed for qualitative traits (i.?e. growth habit, blooming time, intensity of flowering, fruit setting, ripening time, productivity, and fruit shape and color) among pear accessions. As for the quantitative traits, significant variation was observed for leaf area (8.96–27.17 cm²), flowering duration (11–24 days), fruit weight (68.1–322.3 g), average fruit length (2.68–9.87 cm) and average fruit width (1.82–8.12 cm) between pear accessions. Based on qualitative and quantitative data, two dendograms were constructed by using cluster analysis which separated pear accessions into three distinct groups. The cluster analysis showed considerable differences between the accessions for qualitative and quantitative traits. Furthermore, a close association between accessions was noted inside the clusters for qualitative and quantitative traits. The results showed rich diversity and similarity between the pear accessions and needs further assessment at molecular level to elucidate their phylogenetic relationship.     

Associating chemical analysis to molecular markers for the valorization of <Emphasis Type="Italic">Citrus aurantium</Emphasis> leaves: a useful starting point for marker-assisted selection

Variation in metabolite composition and content is often observed in citrus, however, it is poorly understood to what extent this variation has a genetic basis. C. aurantium genotypes originating from Tunisia were evaluated to detect genomic (SSR markers) and chemotypic polymorphisms and to discover possible associations between them. A total of fifteen highly polymorphic SSR markers were selected to screen the genetic variability of the most widespread sour orange genotypes. Targeted secondary metabolite profiling analysis generated twenty-one compounds differentially accumulated in the leaves of sour orange genotypes. PCA analysis revealed that genomic and chemotypic data generated similar pattern of clustering, highlighting the intra-specific variability in C. aurantium species. Both data were integrated, leading to the identification of associated SSR alleles with secondary metabolites. Based on results, a relatively high correlation (r = 0.381; p < 0.0001) between chemotypic patterns and genetic markers was identified. Associations between traits of interest for phenolic compounds and genetic markers were tested using statistical methods including three linear model approaches. These results consolidate the presence of a chemical fingerprint that may be suitable for assessing identity and quality of a particular genotype which will be very useful for citrus breeding programs.