Abstract. The fry of four species of planktivorous carp, silver carp, Hypophthalmichthys molitrix (Valenciennes), bighead carp, Aristichthys nobilis (Richardson), rohu, Labeo rohita (Hamilton), and catla, Catla catla (Hamilton), were grown in monoculture in ponds in Mymensingh, Bangladesh in order to determine electivity and the extent of dietary overlap. Other than an avoidance for Cyanobacteria, electivity was found to be low in most instances, although the low productivity of the ponds may have had some influence. Dietary overlap was greatest between catla and silver carp (0–52) and between catla and bighead carp (0–48).

The outbreak of COVID-19 has caused more than 200,000 deaths so far in the USA alone, which instigates the necessity of initial screening to control the spread of the onset of COVID-19. However, screening for the disease becomes laborious with the available testing kits as the number of patients increases rapidly. Therefore, to reduce the dependency on the limited test kits, many studies suggested a computed tomography (CT) scan or chest radiograph (X-ray) based screening system as an alternative approach. Thereby, to reinforce these approaches, models using both CT scan and chest X-ray images need to develop to conduct a large number of tests simultaneously to detect patients with COVID-19 symptoms. In this work, patients with COVID-19 symptoms have been detected using eight distinct deep learning techniques, which are VGG16, InceptionResNetV2, ResNet50, DenseNet201, VGG19, MobilenetV2, NasNetMobile, and ResNet15V2, using two datasets: one dataset includes 400 CT scan and another 400 chest X-ray images. Results show that NasNetMobile outperformed all other models by achieving an accuracy of 82.94% in CT scan and 93.94% in chest X-ray datasets. Besides, Local Interpretable Model-agnostic Explanations (LIME) is used. Results demonstrate that the proposed models can identify the infectious regions and top features; ultimately, it provides a potential opportunity to distinguish between COVID-19 patients with others.

Salinity, one of the major environmental constraints, threatens soil health and consequently agricultural productivity worldwide. Acacia auriculiformis, being a halophyte, offers diverse benefits against soil salinity; however, the defense mechanisms underlying salt-tolerant capacity in A. auriculiformis are still elusive. In this study, we aimed to elucidate mechanisms regulating the adaptability of the multi-purpose perennial species A. auriculiformis to salt stress. The growth, ion homeostasis, osmoprotection, tissue tolerance and Na+ exclusion, and anatomical adjustments of A. auriculiformis grown in varied doses of seawater for 90 and 150 days were assessed. Results showed that diluted seawater caused notable reductions in the level of growth-related parameters, relative water content, stomatal conductance, photosynthetic pigments, proteins, and carbohydrates in dose- and time-dependent manners. However, the percent reduction of these parameters did not exceed 50% of those of control plants. Na+ contents in phyllodes and roots increased with increasing levels of salinity, whereas K+ contents and K+/Na+ ratio decreased significantly in comparison with control plants. A. auriculiformis retained more Na+ in the roots and maintained higher levels of K+, Ca2+ and Mg2+, and K+/Na+ ratio in phyllodes than roots through ion selective capacity. The contents of proline, total free amino acids, total sugars and reducing sugars significantly accumulated together with the levels of malondialdehyde and electrolyte leakage in the phyllodes, particularly at day 150th of salt treatment. Anatomical investigations revealed various anatomical changes in the tissues of phyllodes, stems and roots by salt stress, such as increase in the size of spongy parenchyma of phyllodes, endodermal thickness of stems and roots, and the diameter of root vascular bundle, relative to control counterparts. Furthermore, the estimated values for Na+ exclusion and tissue tolerance index suggested that A. auriculiformis efficiently adopted these two mechanisms to address higher salinity levels. Our results conclude that the adaptability of A. auriculiformis to salinity is closely associated with ion selectivity, increased accumulation of osmoprotectants, efficient Na+ retention in roots, anatomical adjustments, Na+ exclusion and tissue tolerance mechanisms.

The aim of the current study was to find out the effect of adding different levels of lemon extract to the chicken meatballs. Fresh lemon extract was incorporated into freshly prepared meatball and compared with 0.01 % beta hydroxyl toluene (BHT) and control (without antioxidant). For this purpose, chicken meatball samples were divided into four treatment groups; viz. T0 (Control), T1 (0.01% BHT), T2 (0.5 % lemon extract) and T3 (1 % lemon extract). The study was conducted in completely randomized factorial design. The samples were analyzed for determination of sensory, proximate components, physicochemical, biochemical and microbiological qualities at 0, 30th and 90th days of preservation. Color, flavor, Juiciness, tenderness and overall acceptability increased significantly (p<0.05) among different treatment groups than control and BHT group but decreased at different days of intervals. Dry matter (DM) content decreased significantly (p<0.05) with different treatment levels than control and BHT group and increased with days of intervals. Crude protein (CP), ether extract (EE) and Ash of all treatments were decreased significantly (p<0.05) among different treatment groups. Raw pH, cooked pH and cooking loss were decreased significantly (p<0.05) with different treatment levels than control and BHT group and decreased with days of intervals. Free fatty acid (FFA), peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) value were decreased significantly (p<0.05) with different treatment levels than that of control and BHT group and increased with days of intervals. Total viable count (TVC), total coli form count (TCC) and total yeast mould count (TYMC) decreased significantly (p<0.05) at different treatment levels than that of control and BHT group. Therefore, it can be concluded that 1 % lemon extract for formulation of value-added chicken meatballs was enriched source as natural antioxidant. SAARC J. Agri., 18(2): 139-156 (2020)

A study on problems and prospects of shrimp production and marketing from Bangladesh on the basis of secondary information was carried out from July to October 08. Shrimp farming has emerged one of the important economic activities in Bangladesh and become the second largest export industry after garments. Shrimp aquaculture in coastal areas plays a major role providing employment, income and food security to remote coastal people where alternative livelihood options are limited. Shrimp culture system is extensive to improved extensive type with total production of 55000 mt of brackish water shrimp and 12000 mt of freshwater shrimp. In coastal Bangladesh, shrimp culture has led to many social and environmental problems. In export markets, shrimps are great but many challenges remain ahead because of increasing requirements of quality, food hygiene and development of technological and trade barriers in large shrimp markets in USA and EU countries. However, challenges lies with good aquaculture practice and competitive export, which are the effective tools for poverty alleviation and national development program for Bangladesh.