Seasonality of cattle feed sources in Pabna,Bangladesh

Summary Cattle feed sources were studied at village level in Pabna district, Bangladesh. A large quantity of feed was offered. In the monsoon the average amount of DM fed to a mature animal of 210kg was 7·1kg d⁻¹, consisting of about equal amounts of straw, weeds and leaves. In winter animals grazed for an average of 3·7hd⁻¹ and were supplemented with 3·9kgDMd⁻¹ (two-thirds straw). In summer they were offered 5·4kgDMd⁻¹ (one-third straw and two-thirds weeds and leaves) and they grazed for 0·5hd⁻¹. The major limiting constraint on cattle production is the quality of the feed offered, particularly in the monsoon period when animals cannot graze. In future, feed quality will become even more of a problem because grazing lands are gradually disappearing.

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Resumen Se estudiaron las fuentes de alimentos para el ganado a nivel de villorrio en el distrito de Pabna, Bangladesh. Se ofreció gran cantidad de alimento. En la época de monsones, la cantidad promedio de materia seca (MS) suministrada a un animal maduro de 210kg fue 7·1kgd⁻¹, la que consistió en cantidades iguales de paja, malezas y hojas. En invierno los animales pastorearon un promedio de 3·7hd⁻¹ y fueron suplementados con 3·9kgMSd⁻¹ (dos tercios paja). En verano se ofrecieron 5·4kgMSd⁻¹ (un tercio paja y dos tercios malezas y hojas), pastoreando los animales 0·5hd⁻¹. La mayor limitante encontrada, fue la calidad del alimento ofrecido, particularmente en la época de monsones, cuando los animales no pueden pastorear. En el futuro, la calidad del alimento empeorará, ya que las pasturas están desapareciendo gradualmente.

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Résumé Les disponibilités alimentaires du bétail ont été étudiées dans le district de Pabna (Bangladesh), au sein d'un village. Une grande quantité de nourriture fut offerte. Lors de la mousson, la quantité moyenne de matière sèche présentée à un adulte de 210kg était de 7,1kg/j, consistant en proportion à peu près équivalente de paille, mauvaises herbes et feuilles. En hiver, les animaux paturaient en moyenne 3,7kg/j et recevaient un supplément de 3,9kg/j de matières sèchs (deux tiers de paille). En été, on leur a distribué 5,4kg/j de matières sèches (un tiers de pailles, deux tiers de mauvaises herbes et de feuilles) et ils paturaient pendant une demi-heure (0,5h/j). Le facteur majeur limitant réside dans la qualité nutritive offerte, particulièrement pendant la mousson, période où les animaux ne peuvent pas paturer. La qualité de l'alimentation risque de devenir encore plus problématique du fait de la disparition progressive des paturages.

     

Marine-Derived Chitosan Nanoparticles Improved the Intestinal Histo-Morphometrical Features in Association with the Health and Immune Response of Grey Mullet (Liza ramada)

Marine-derived substances are known for their beneficial influences on aquatic animals’ performances and are recommended to improve intestinal health, immunity, and anti-oxidative status. The present study investigates the role of chitosan nanoparticles on the intestinal histo-morphometrical features in association with the health and immune response of Grey Mullet (Liza ramada). Chitosan nanoparticles are included in the diets at 0, 0.5, 1, and 2 g/kg and introduced to fish in a successive feeding trial for eight weeks. The final body weight (FBW), weight gain (WG), and specific growth rate (SGR) parameters are significantly increased while feed conversion ratio (FCR) decreases by chitosan nanoparticles compared to the control (p < 0.05). The morphometric analysis of the intestines reveals a significant improvement in villus height, villus width, and the number of goblet cells in chitosan-treated groups in a dose-dependent manner. Additionally, there is a positive correlation between the thickness of the enterocyte brush border and the chitosan dose, referring to an increasing absorptive activity. Histologically, the intestinal wall of Grey Mullet consists of four layers; mucosa, sub-mucosa, tunica muscularis (muscular layers), and serosa. The histological examination of the L. ramada intestine shows a normal histo-morphology. The epithelial layer of intestinal mucosa is thrown into elongated finger-like projections, the intestinal villi. The values of hemoglobin, hematocrit, red blood cells (RBCs), total protein (TP), albumin, and globulin are significantly increased in fish fed 1, and 2 g/kg of chitosan nanoparticles compared to fish fed 0 and 0.5 g/kg (p < 0.05). The highest levels of TP and albumin are observed in fish fed 1 g/kg diet (p < 0.05). The lysozyme activity and phagocytic index are significantly enhanced by feeding chitosan nanoparticles at 0.5, 1, and 2 g/kg, whereas the phagocytic activity is improved in fish fed 1 and 2 g/kg (p < 0.05). The highest lysozyme activity and phagocytic index are observed in fish fed 1 g/kg. SOD is significantly activated by feeding chitosan nanoparticles at 1 g/kg. Simultaneously, glutathione peroxidase (GPx) and catalase (CAT) activities also are enhanced by feeding chitosan at 1 and 2 g/kg, compared to fish fed 0 and 0.5 g/kg (p < 0.05). The highest GPx and CAT activities are observed in fish fed 1 g/kg (p < 0.05). Conversely, the malondialdehyde (MDA) levels are decreased by feeding chitosan at 1 and 2 g/kg, with the lowest being in fish fed 1 g/kg (p < 0.05). To summarize, the results elucidate that L. ramada fed dietary chitosan nanoparticles have a marked growth rate, immune response, and anti-oxidative response. These improvements are attributed to the potential role of chitosan nanoparticles in enhancing intestinal histo-morphometry and intestinal health. These results soundly support the possibility of using chitosan nanoparticles at 1–2 g/kg as a feasible functional supplement for aquatic animals.     

Physiological response,blood chemistry profile and mucus secretion of red sea bream (<Emphasis Type="Italic">Pagrus major</Emphasis>) fed diets supplemented with <Emphasis Type="Italic">Lactobacillus rhamnosus</Emphasis> under low salinity stress

Environmental stressors caused by inadequate aquaculture management strategies suppress the immune response of fish and make them more susceptible to diseases. Therefore, efforts have been made to relieve stress in fish by using various functional feed additives in the diet, including probiotics. The present work evaluates the effects of Lactobacillus rhamnosus (LR) on physiological stress response, blood chemistry and mucus secretion of red sea bream (Pagrus major) under low salinity stress. Fish were fed four diets supplemented with LR at [0 (LR0), 1 × 10² (LR1), 1 × 10⁴ (LR2) and 1 × 10⁶ (LR3) cells g^?1] for 56 days. Before stress, blood cortisol, urea nitrogen (BUN) and total bilirubin (T-BIL) showed no significant difference (P > 0.05), whereas plasma glucose and triglyceride (TG) of fish-fed LR2 and LR3 diets were significantly lower (P < 0.05) than those of the other groups. Plasma total cholesterol (T-CHO) of fish-fed LR3 diet was significantly (P < 0.05) lower than that of the other groups. Furthermore, total plasma protein, mucus myeloperoxidase activity and the amount of mucus secretion were significantly enhanced in LR-supplemented groups when compared with the control group (P < 0.05). After the application of the low salinity stress test, plasma cortisol, glucose, T-CHO and TG contents in all groups showed an increased trend significantly (P < 0.01) compared to the fish before the stress challenge. However, plasma total protein and the amount of secreted mucus showed a decreased trend in all groups. On the other hand, BUN, T-BIL and mucus myeloperoxidase activity showed no significant difference after exposure to the low salinity stress (P > 0.05). In addition, the fish that received LR-supplemented diets showed significantly higher tolerance against low salinity stress than the fish-fed LR-free diet (P < 0.05). The physiological status and the detected immune responses, including total plasma protein and mucus myeloperoxidase activity in red sea bream, will provide a more comprehensive outlook of the effects of probiotics to relieve stress in fish.     

Effects of dietary protein and lipid levels on growth performance,fatty acid composition and antioxidant‐related gene expressions in juvenile loach Misgurnus anguillicaudatus

Dojo loach (Misgurnus anguillicaudatus) is one of the most important cultured freshwater fish in several East Asian countries. However, a little information is available in its nutritional requirements. Thus, this study was conducted to evaluate the effects of feeding varying levels of dietary protein and lipid on growth, fatty acid composition and antioxidant‐related gene expressions in juvenile loach. Six practical diets at three levels of protein (30%, 40% and 50%) and two levels of lipid (6% and 12%) were fed to loach juveniles (initial weight 0.40 g) in triplicated groups (20 fish per replicated) for a period of 8 weeks. Results showed that regardless of lipid level, body weight gain of fish was significantly increased with incremental dietary protein level. Meanwhile, feed conversion ratio was significantly decreased by dietary protein levels, and the lowest value was observed in fish fed dietary protein levels of 50%, regardless of dietary lipid level. Moreover, the percentage of 22:6n‐3 in viscera was significantly increased by different protein levels. The expression level of catalase was significantly increased with incremental dietary protein level with both lipid levels. Meanwhile, the expression level of hepatic nuclear factor erythroid 2‐related factor 2 (Nrf2) was downregulated with incremental dietary protein level with 6% of lipid level, but the expression was upregulated with incremental dietary protein level with 12% of lipid level. In conclusion, these data suggested that 6% lipid and 50% protein in diet was optimal for loach during early development stage.     

The nature and consequences of co-infections in tilapia: A review

Co-infections commonly arise when two or multiple different pathogens infect the same host, either as simultaneous or as secondary concurrent infection. This potentiates their pathogenic effects and leads to serious negative consequences on the exposed host. Numerous studies on the occurrence of the bacterial, parasitic, fungal and viral co-infections were conducted in various tilapia species. Co-infections have been associated with serious negative impacts on susceptible fish because they increase the fish susceptibility to diseases and the likelihood of outbreaks in the affected fish. Co-infections can alter the disease course and increase the severity of disease through synergistic and, more rarely, antagonistic interactions. In this review, reports on the synergistic co-infections and their impacts on the affected tilapia species are highlighted. Additionally, their pathogenic mechanisms are briefly discussed. Tilapia producers should be aware of the possible occurrence of co-infections and their effects on the affected tilapia species and in particular of the clinical signs and course of the disease. To date, there is still limited information regarding the pathogenicity mechanisms and pathogen interactions during these co-infections. This is generally due to low awareness regarding co-infections, and in many cases, a dominant pathogen is perceived to be of vital importance and hence becomes the target of treatment while the treatment of the co-infectious agents is neglected. This review article aimed at raising awareness regarding co-infections and helping researchers and fish health specialists pay greater attention to these natural cases, leading to increased research and more consistent diagnosis of co-infectious outbreaks in order to improve control strategies to protect tilapia when infected with multiple pathogens.     

Antiparasitic activity of the medicinal plant Dillenia suffruticosa against the marine leech Zeylanicobdella arugamensis (Hirudinea) and its phytochemical composition

Zeylanicobdella arugamensis (Annelida: Hirudinea), a marine parasitic leech, is currently affecting different species of cultured groupers, hybrid groupers, snappers and sea bass in Malaysia. Dillenia suffruticosa (Dilleniaceae), a medicinal plant found in Sabah, has been selected in our experiment to kill the leeches as a natural control method. The leech‐infested hybrid groupers were collected from aquaculture facilities, and the isolated leeches were challenged against methanol extract of D. suffruticosa leaves. The experiment was carried out using various concentrations of the extracts such as 25, 50 and 100 mg/ml. The methanol extract showed significant antiparasitic activity against Z. arugamensis with 100% mortality at a concentration of 100 mg/ml in 14.39 ± 3.75 min., followed by 50 and 25 mg/ml in 32.97 ± 9.29 and 41.77 ± 5.40 min., respectively. The phytochemical composition of the extract was determined using GC‐MS analysis to understand the nature of the principal compounds responsible for its antiparasitic properties. The leaves of D. suffruticosa demonstrated the presence of different bioactive compounds of various natures with varying percentages. Thus, it could be revealed that the methanol extract of D. suffruticosa mainly contains vital phytochemical compounds and showed an effective antiparasitic activity against the harmful leeches of hybrid groupers.     

Replacement of squid and krill meal by snail meal (Buccinum striatissimum) in practical diets for juvenile of kuruma shrimp (Marsupenaeus japonicus)

A 60‐day feeding trial was conducted to investigate the effects of substituting squid and krill meal with marine snails (Buccinum striatissimum) into the diets of juvenile kuruma shrimps (Marsupenaeus japonicus). Five experimental diets were formulated to contain varying levels of snail meal at 0%, 25%, 50%, 75% and 100% (D1, D2, D3, D4 and D5, respectively) and fed to juvenile kuruma shrimps (initial mean weight 0.27 ± 0.02 g). The results showed that weight gain, feed intake and specific growth rate were improved significantly in D4 and D5 groups when compared with D1 group (p < 0.05). Significant differences were not detected in survival rate among all shrimps fed diets containing several levels of snail meal (p > 0.05). Crude protein content of shrimps fed the control diet was significantly lower than other treatments (p < 0.05). Lipid content in shrimps fed 50% snail meal were significantly higher than the control while cholesterol content in shrimps fed 100% snail meal were significantly decreased and polyunsaturated fatty acid contents were significantly increased in shrimps fed 75%–100% snail meal (p < 0.05). These results suggest that supplementing snail meal for complete replacement of squid and krill meal can be done to improve juvenile kuruma shrimps’ growth and reducing their cholesterol levels.     

Is the use of recombinant cGnRH may be a future alternative to control the fish spawning? Let us go with the goldfish example

The use of recombinant gonadotropin-releasing hormone (rGnRH) has very rarely been tested in fish to promote spawning. This study evaluated the impact of recombinant chicken gonadotropin-releasing hormone (rcGnRH) with metoclopramide on the release of sex steroids and final maturation induction in goldfish (Carassius auratus) broodstock. For this purpose, goldfish broodstock was divided into four groups and treated with 0.9% NaCl with 20 mg/kg metoclopramide (Met) (C); 10 μg/kg body weight (BW) rcGnRH with 20 mg/kg metoclopramide (rcGn10); 15 μg/kg BW rcGnRH with 20 mg/kg metoclopramide (rcGn15); and 20 μg/kg BW rcGnRH with 20 mg/kg metoclopramide (rcGn20). The capability of the rcGnRH for eliciting biological response was tested in vivo by evaluating the changes of 17β estradiol (E2), testosterone (T), and 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) and the induced spawning. Blood samples were obtained at 0 h, 12 h, and 24 h after injection. The rcGn10, rcGn15, and rcGn20 treatments induced lower E2 concentration, especially 24 h post-injection. T levels were significantly higher in rcGn10, rcGn15, and rcGn20 treatments 12 h post-injection than at 0 h and then decreased at 24 h post-injection. Furthermore, the rcGnRH tested significantly enhanced DHP secretion in rcGn10, rcGn15, and rcGn20 treatments 12 h post-injection before a decline at 24 h post-injection. No significant difference between the sampling times was found in the C treatment for the 3 sex steroids tested. The results also displayed that rcGnRH at 10–20 µg/kg of body weight can trigger spawning with the highest speed and efficiency of spawning at 20 µg/kg. The obtained results represent a possible strategy for enhancing the artificial reproduction and ovulation of broodstock fish by rGnRH and further support the use of recombinant hormones to promote reproduction in aquaculture.

     

Physiological response of lupine and associated weeds grown at salt-affected soil to α‑tocopherol and hoeing treatments

About 900.000 ha of Egypt’s agricultural lands are suffering from salinity build-up problem. Therefore, two field experiments were conducted in split-split plot design with four replications to study α?tocopherols foliar application with 100 and 200 ppm and hand hoeing (two and three hand hoeing, plus unweeded) and their interactive effects on growth, osmoprotectants, mineral contents, seed yield, yield components, and nutritive value of the lupine plants and its associated weeds grown under salt-affected soil at 1.30, 3.20 and 4.23 dS m^?1. Three hand hoeing treatment achieved the highest weed depression expressed in the lowest number and dry matter of broad-leaved, narrow-leaved and total weeds, and reduction % in dry matter were 80.75, 78.25 and 79.26 % compared with unweeded, respectively. Salinity stress significantly decreased total chlorophyll content, leaf area index and plant dry weight, while α?tocopherol and hoeing increased in all previous traits relative to corresponding controls. Lupine seed yield, yield components, and oils, carbohydrates, proteins, carotenoids and alkaloids in the yielded seeds were significantly reduced by increasing salinity levels, meanwhile hoeing and α?tocopherol treatments improved them. Total essential amino acids were decreased by increasing salinity levels and increased by increasing α?tocopherol concentrations and number of hoeing treatments. It could be concluded that α?tocopherol especially at 200 ppm partially alleviated the harmful effects of salinity stress on the growth of lupine plants and nutritive value of the yielded seeds. Three hand hoeing treatment was the optimum and safe method in controlling weeds associated with lupine plant grown under salinity stress.