Mean Lipid Content Research Articles

Individually Cultured Bovine Zygotes Successfully Develop to the Blastocyst Stage in an Extremely Confined Environment

The possibility of detecting the developmental competence of individually cultured embryos through analysis of spent media is a major current trend in an ART setting. However, individual embryo culture is detrimental compared with high-density group culture due to the reduced concentration of putative embryotropins. The main aim of this study was to identify an individual culture system that is not detrimental over high-density group culture in the bovine model. Blastocyst rates and competence were investigated in a conventional (GC) group, semi-confined group (MG), and individual culture (MS) in a commercial microwell device. Main findings showed that: (1) individual embryos can be continuously cultured for 7 days in ~70 nL microwells (MS) without detrimental effects compared with the GC and MG; (2) MS and MG blastocysts had a reduced number of TUNEL-positive cells compared to GC blastocysts; (3) though blastocyst mean cell numbers, mitochondrial activity, and lipid content were not different among the three culture conditions, MS blastocysts had a higher frequency of small-sized lipid droplets and a reduced mean droplet diameter compared with GC and MG blastocysts. Overall, findings open the way to optimize the development and competence of single embryos in an ART setting.

Quantitative estimation of metabolites and antifungal efficacy of leaf extracts <i>Aspilia africana</i> on cucumber and pawpaw fruit spoilage fungi

Several reports have shown that about 25% of harvested fruits globally are lost to spoilage by microorganisms. The study determined the quantitative metabolites and bioactivities of Aspilia africana extracts on fungi from spoiled Cucumis sativus and Carica papaya fruits. The fungi from spoiled C. sativus and C. papaya fruits were obtained using mycological techniques. The quantitative metabolites and bioactivities of the aqueous (ALEAA) and ethanol (ELEAA) extracts of A. africana were determined using the standard protocol and disc diffusion technique, respectively. The fungal genera obtained were Aspergillus, Penicillium, Mucor, Fusarium, and Rhizopus. There were variations in percentage yields, physical appearances, and pH of the extracts. The results of quantitative estimation of metabolites showed that ALEAA had mean protein, carbohydrate, and lipid contents of 15.36 ± 0.32%, 60.97 ± 1.14%, and 6.66 ± 0.04%, respectively. Alkaloids showed a positive correlation with protein (r = 0.2028) and carbohydrate (r = 0.421), and a negative correlation with lipid (r = -0.6556) at p < 0.05. The ELEAA exhibited more inhibitory effects on test fungal isolates, with mean zones of inhibition (IZs) ranging from 9.3 ± 0.1 to 18.8 ± 0.3 mm, than the ALEAA, with mean IZs ranging between 9.4 ± 0.4 and 16.0 ± 1.0 mm. The R coefficients of the extracts and IZs as exhibited by the fungi ranged from 0.5985 to 0.9936. The results have revealed quantitative metabolites and antifungal activities of the extract and also provided rationale for its utilization as a preservative for fruits against spoilage by fungi.

English

laxseed (Linum usitatissimum L.) oil is an important crop in China, which is rich in saturated fatty acids, alpha-linolenic acid, and other essential nutrients for the human body. Here, we investigated the effects of different irrigation and fertilization conditions on flax yield and quality in semi-arid regions in northern China. Using non-weighing lysimeter fertilization versus non-fertilization, the effects of four irrigation treatments (1 500, 1 800, 2 100, and 2 400 m3 ha-1) on flax yield and quality were assessed for the flax cultivar ‘Yajin7.’ As the irrigation quota increased, both the aboveground fresh weight and flaxseed biomass initially increased and subsequently decreased. The flax fresh weight and seed weight increased by 74.52 and 80.70%, at irrigation quotas of 2 100 and 1 500 m3 ha-1, respectively; however, irrigation quota had no significant effect on flax quality. Fertilizer application significantly improved flax and flaxseed yields by 127 and 77%, respectively, increased mean flax protein content from 20.05 to 24.63%, and decreased the mean lipid content from 46.52 to 43.67%. However, fertilization had no effect on the content of palmitic, stearic, oleic, linoleic, and linolenic acids. Overall, our results highlight that water related benefits to flax crops decrease in response to increasing the irrigation quota and appropriate fertilizer application can significantly improve flax yield and quality. Therefore, this study provides a theoretical basis for irrigation and fertilization related to flax cultivation in northern China

Comparisons of morphometrics and body condition between two breeding populations of Australian humpback whales

Context The east and west coasts of Australia form the breeding grounds for two of the world’s largest and fastest-growing populations of humpback whales (Megaptera novaeangliae). These populations show differences in mean lipid content, fatty acid profiles, and stable isotope values. Aims To determine whether these differences result in variation in nutritional health and physiology between populations, we quantified and compared the morphology, body condition and energetic requirements between the two populations. Methods We used unmanned aerial vehicles to measure body morphometrics (residual of body volume vs length) of humpback whales from May to November in 2017, 2020 and 2021. Key results Morphometric measurements were obtained from 973 humpback whales (119 calves, 249 juveniles, 486 adults, and 119 lactating females). Results showed that the two populations did not differ significantly in their morphology. The average body condition was significantly different for sexually mature reproductive classes, with adults and lactating females on the west coast having a lower body condition, by an average of 7.7 and 11.1 percentage points below the east coast population respectively. All reproductive classes, with the exception of calves followed a similar pattern in body condition loss through the breeding season. Calves on the east coast exhibited a curvilinear relationship with days post-partum, with early and late-migrating calves being in poorer body condition than were those migrating mid-season. In contrast, west coast calves did not significantly change their condition through the breeding season. Conclusions The poorer body condition of sexually mature individuals in the west coast population is concerning, given the overall condition loss during a breeding season. This difference could be influenced by variations in sampling time; however, differences in feeding opportunities, climatic regimes and/or environmental variables may influence the ability of one population to acquire similar amounts of energy. Implications The difference in body condition between these two humpback whale populations highlighted the need to assess populations individually, so as to develop representative levels that can be used for future conservation monitoring and management.

Proximate Composition of Some Selected Seaweeds from Coastal Areas of Cox’s Bazar and the St. Martin’s Island, Bangladesh

The present study assesses the proximate composition of eight wild seaweed species viz. Hypnea sp., Enteromorpha sp., Sargassum sp., Hydroclathrus clathratus, Padina pavonica, Colpomenia sinuosa, Petalonia fascia and Dictyota ciliolata and one cultured species viz. Hypnea sp. collected from western coast of the St. Martin’s Island and Nunairchhara, Cox’s Bazar, respectively. Standard analytical methods were used to estimate moisture, ash, lipid, crude fiber and protein contents, while carbohydrates were measured by subtracting ash, fat, fiber and protein contents from 100 on a dry weight basis. Results showed average moisture content in different seaweed species ranged between 12.09% to 29.65% and varied from species to species. Maximum ash content was found in brown seaweed H. clathratus (61.98%), while the lowest was recorded in wild red algae Hypnea sp. (7.05%). This study showed mean lipid contents in all seaweed species were much lower than other contents of proximate composition. The highest crude fiber content was observed in P. fascia (10.08±0.07%), while the lowest was observed in Enteromorpha sp. (0.23±0.01%). The highest protein (23.64±1.44%) and carbohydrate content (46.71±0.54%) was found in Hypnea sp. This study showed that mean carbohydrate content was higher in Rhodophyta, Chlorophyta and Phaeophyta, whereas, lipid content was lower in the three groups. Proximate composition of ash, lipid, crude fiber and protein content within species varied due to habitat differences, changes of body structures or physiological alterations, changes in growth rates and photosynthetic function of seaweed species and geographical differences. The mean moisture and ash content were the highest in cultured Hypnea sp., whereas, lipid, crude fiber, protein and carbohydrate were formed to the highest in wild Hypnea sp. Results suggest wild Hypnea sp. was much nutritive because of having higher amount of protein, fiber, carbohydrate and lipid than cultured ones. The study indicates that seaweeds might be used as a potential source of protein, fiber and carbohydrate. The Dhaka University Journal of Earth and Environmental Sciences, Centennial Special Volume June 2022: 113-122

Nutritional potentiality of earthworm (Perionyx excavatus) for substituting fishmeal used in local feed company in Bangladesh

Nutritional composition of wild earthworm (Perionyx excavatus) and fishmeal used by local fish-feed industry in Bangladesh was determined to evaluate the nutritionally replacement potentiality of this earthworm species for fishmeal mostly used in feed for aquaculture and other animal production. Except for moisture content, the proximate chemical values in P. excavatus did not differ significantly (P≥0.05) from that in fishmeal. On an average, the earthworm had lower protein content (46.57 ± 0.97%) than fishmeal had (54.97 ± 7.49 %). On the other hand, the mean lipid content (8.03 ± 0.44 %) in this earthworm was found to be higher compared to fishmeal (7.97 ± 1.60 %). The average ash content in the earthworm and fishmeal were 24.26 ± 0.68 % and 24.13 ± 8.44 %, respectively. The results of the present study indicate that this earthworm species had almost similar nutritional values to the fishmeal, and thus would be a potential source of animal protein in supplementing fishmeal. In an implication, year-round production of this earthworm species through standard mass culture system, and its radical use could play a pivotal role in sustainable fisheries and aquaculture production.

Biochemical Composition and Microorganisms Associated with Senilia senilis (Linnaeus, 1758) in Mangrove Swamps of Iko Estuary, Southeast, Nigeria

The bloody cockle (Senilia senilis), has been harvested by humans over thousands of years and can therefore be a good candidate for assessing past variations of key environmental parameters. Proximate and Microbes associated with S. senilis were evaluated as indices for food safety and biomarker of pollution. Standard microbiological techniques and standard methods of AOAC were employed. Results showed that Bacillus subtilis, Micrococcus species, Proteus species, Klebsiella species, Staphylococcus aureus, Vibrio cholerea, Vibrio parahaemolyticus, Enterobacter sp, Escherichia coli, Bacillus cereus, and Chromatium species were the probable bacteria while Rhizopus stolonifer, Aspergillus niger, Penicillium species, Candida tropicalis, Fusarium species and Aspergillus flavus were the probable fungi isolated from the sample. The mean crude protein, moisture, carbohydrate, ash, lipid and crude fibre contents of the soft tissues were 55.86±2.80, 45.01±1.73, 28.59±2.88, 5.96±0.35, 6.61±0.81 and 4.52±0.19% respectively, while the energy or caloric value was 397.65±11.97 Kcal. The mean Total Heterotrophic Bacterial Count, Total Vibrio Count, Total Coliform Count, Total Salmonella Shigella, Total Staphylococcus Count and Total Fungal Count in fresh sample were 1.72±0.85x105, 7.62±1.11x10, 3.33±1.73x10, 2.40±0.14x102, 2.08±0.21x101 and 3.33±0.68x104 cfu g-1 respectively and concentrated mostly in the gut. Although, S. senilis is highly nutritious, the high microbial load make its consumption life threatening. Proper monitoring and surveillance should therefore be adopted by Government and non-governmental agencies to check pollution of the aquatic environments and proper processing should be adopted before consumption for good public health.

Microbiological and Proximate Evaluation of Knife Clam (Tagelus Adansonii, Bosc, 1801) from Okoro River, Eastern Obolo, Nigeria.

Tagelus adansonii has served as man’s food around the world from time immemorial. However, the aquatic ecosystem in which they live is constantly polluted. Microbial and proximate compositions and energy value of T. adansonii were evaluated as indices for food safety and biomarker of pollution. Standard microbiological techniques and standard methods of AOAC were employed. Results showed that Bacillus substilis, Micrococcus sp, Proteus sp, Klebsiella sp, Staphylococcus aureus, Vibrio cholerea, Vibrio parahaemolyticus, Enterobacter sp, Escherichia coli, Bacillus cereus, and Chromatium sp were the probable bacteria while Rhizopus stolonifer, Aspergillus niger, Penicillium sp. Candida tropicalis, Fusarium sp. and Aspergillus flavus were the probable fungi isolated from the sample. Total Heterotrophic Bacterial Count (THBC), TVC, TCC, TSC and TFC in fresh sample were 2.01±0.14 x 105, 2.77±0.27x10, 2.79±0.81x10, 6.08±0.21x102, and 2.08±0.21x104 cfu g-1 respectively and concentrated mostly in the gut. The mean crude protein, moisture, carbohydrate, ash, lipid and crude fibre contents of the soft tissues were 60.92±2.38, 40.75±1.85, 26.58±2.91, 5.99±0.43, 5.56±0.51 and 4.13±0.10% respectively while the energy or caloric value was 397.65±11.97. Proper monitoring and surveillance should be adopted by Government to check pollution of the aquatic environments and proper processing should be adopted before consumption for good public health.

Effect of hatching time and starvation on morphometrics and biochemical composition of Octopus tetricus paralarvae

Rearing paralarvae of merobenthic octopus species from hatch to their benthic phase remains a difficult task, mainly due to unsuitable diets. Knowledge of their nutritional requirements is therefore crucial to providing appropriate diets. This study tracked changes in morphometrics and biochemical composition of Octopus tetricus paralarvae from the same brood that hatched at different times, and in starved paralarvae. Mean wet weight, dry weight, mantle length, arm length and protein content were highest in paralarvae that hatched at 0 days postfirst hatch, while the mean lipid content of paralarvae was not affected by hatching times. The mean wet weight of starving paralarvae continuously decreased, while the dry weight showed two distinctive declines between 0–1 dph and 3–5 dph. Both total length and mantle length were longest in paralarvae aged 0–1 dph compared to 4–5 dph under starving conditions. Paralarvae mean lipid content did not differ due to starving period but mean protein content decreased continuously. The most abundant fatty acids in paralarvae were DHA, EPA, palmitic acid and stearic acid across both experiments. The tendency of the protein content of developing and starved paralarvae to decline, while the overall lipid content remained largely unchanged, suggests that proteins were mainly catabolized, further indicating their importance for the formulation of artificial diets for octopus paralarvae.

Effect of boiling and oven roasting on some physicochemical properties of sunflower seeds produced in Far North, Cameroon.

The effects of different processing methods on proximate composition, total phenolic content, antioxidant activity, lipid oxidation, and mineral contents of sunflower seeds produced in Far North Region of Cameroon were evaluated. Mean moisture, ash, lipid, protein, fiber, and carbohydrate contents of raw sunflower seeds were 6.60%, 2.55%, 44.65%, 20.17%, 4.08%, and 21.25%, respectively. The changes in moisture, ash (excepted in boiled samples), lipid, protein, fiber, and carbohydrate (excepted in roasted samples) were found to be significant for all cooking methods. Ash and lipid contents of samples roasted at 120°C were found to be significant when compared with other cooking methods. Antioxidant activity increased with treatment. After processing, the acid, peroxide, and thiobarbituric acid values increased significantly, whereas iodine value decreased. The roasting process improved the induction time, and samples roasted at 120°C were found to have the highest induction time (2.29 ± 0.09 hr). Raw sunflower seeds were good sources of potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), zinc (Zn), and manganese (Mn). Increase in contents of Ca, Mg, Zn, Cu, and Fe was observed during processing. Roasting compared with boiling appeared to be the best cooking method of sunflower seeds concerning nutrient content, antioxidant stability, and lipid stability.

Comparison of photoautotrophic and mixotrophic cultivation of microalgae Messastrum gracile (Chlorophyceae) in alternative culture media.

Growth and biological conditions of Messastrum gracile were evaluated to compare the effect of photoautotrophic and mixotrophic cultivation on the increase of biomass production and chemical conditions cultured in macrophyte and commercial culture media. The growth rate (k) of M. gracile was different in the culture media, higher in mixotrophic cultivation for Lemna minor culture medium, whilst to Eichhornia crassipes and NPK culture media were higher in photoautotrophic cultivation. Mean lipid contents in photoautotrophic cultivation were 8.2% biomass dry weight, whereas they reached 19% biomass dry weight in mixotrophic cultivation. Protein contents were below 48% biomass dry weight in photoautotrophic cultivation and 30% biomass dry weight in mixotrophic cultivation. Messastrum gracile cultured in macrophyte culture media (E. crassipes and L. minor) and NPK culture medium provided satisfactory results with regard to lipid and protein contents in mixotrophic and photoautotrophic cultivations, respectively. Lipid and protein contents in alternative media were higher or similar to the CHU12 commercial culture medium.

Comparative analysis of chemical composition of some commercially important fishes with an emphasis on various Malaysian diets

AbstractThis study compares the chemical composition of cockle (Anadara granosa) and some commercially important marine (Asian seabass Lates calcarifer, grouper Epinephelus bleekeri, hardtail scad Megalaspis cordyla, longtail tuna Thunnus tonggol and Indian mackerel Rastrelliger kanagurta) and freshwater (sutchi catfish Pangasius hypophthalmus, Nile tilapia Oreochromis niloticus and eel Monopterus albus) fishes in Peninsular Malaysia. The results show that the proximate composition and trace metal content were significantly different (P < 0.05) among species investigated. The mean protein content was the highest in eel (19.1%) and the lowest in sutchi catfish (13.0%) and cockle (13.0%). The mean lipid content of Indian mackerel (3.9%) was higher than cockle (2.0%), followed by eel (1.3%) and longtail tuna (0.8%). The mean ash content was the highest in Indian mackerel (1.4%) and the lowest in cockle (0.9%). Zinc and manganese contents in cockle (Zn: 61.2 mg kg−1, Mn: 22.7 mg kg−1) were very high compared to other species investigated. The copper content was minimum in sutchi catfish (1.0 mg kg−1) and a maximum in the hardtail scad (11.7 mg kg−1). Trace metal content in sutchi catfish, Nile tilapia, grouper, longtail tuna, eel and cockle followed an order Zn > Mn > Cu, whereas Asian seabass, hardtail scad and Indian mackerel followed a different order Zn > Cu > Mn. Trace metal content in the tissue of the fishes examined was within safe limits for human consumption except Mn content in the cockle and Cu content in the hardtail scad, which is a matter of concern. When considering the daily fish fat, mineral and trace metal intake, marine fishes and shellfish are better than freshwater fishes.

Proximal composition and fatty acid profile of fresh and smoked fillets of Pangasius hypophthalmus

The aim of this study was to determine the proximal composition and the fatty acid profile of fresh and smoked fillets of Pangasius hypophthalmus. After brining (4% / 270 min), the salted fillets of Pangasius hypophthalmus were pre-dried at 30 °C for 30 min, then smoked at 30 °C / 120 min; 50 °C/ 240 min and at 80 °C for 240 min. The proximal composition was determined using standard methods and the fatty acid profile was analyzed by GC / MS. The mean water, protein, ash and lipid content of the fresh fillet was 77.32 ± 2.15; 19.66 ± 0.46; 1.24 ± 0.14; and 1.00 ± 0.02% (wet basis), respectively. Smoking had a significant influence (P ˂ 0.05) on the proximal composition, particularly on the protein (28.74 ± 0.25%) and ash (3.94 ± 0.08%) content. After smoking, no significant change (P ˃ 0.05) was observed in the proportion of monounsaturated fatty acids in fish, but the proportions of polyunsaturated fatty acids and saturated fatty acids increased significantly in the smoked fillet compared with the fresh filet. The proportions of fatty acid ω-6 and ω-3 and the ratio ω-6 / ω-3 of fresh fillets of Pangasius hypophthalmus were 33.23, 4.79 and 6.94, respectively; while for smoked fillets the values were 38.40, 5.45 and 7.05, respectively. This study suggests that smoking improves the nutritional value of Pangasius hypophthalmus because of its high protein and PUFA content known for its beneficial health effects.

Application of texture analysis of b-mode ultrasound images for the quantification and prediction of intramuscular fat in living beef cattle: A methodological study

Intramuscular fat (IMF) contributes significantly to the aroma and tenderness of the meat, therefore playing a key role in quality determination. Yet, IMF determination methods rely on visual inspection or on fat extraction from meat samples after animals' slaughter. The aim of this methodological study was the elaboration of a process capable of predicting IMF% using real-time ultrasound (RTU) images in live beef cattle.The longissimus dorsi (LD) muscle of 26 Charolaise heifers was investigated. In vivo ultrasound images were taken and texture analysis was performed. One week after the animals' slaughter, the whole twelfth rib cut was collected, and IMF% was determined by extraction with petrol ether (Randall) method.Animals were divided in 3 groups depending on their mean lipid content percentage in 100 g meat (Group 1: IMF ≤ 4.24%; Group 2: 4.25% ≤ IMF ≤ 5.75%; Group 3: IMF ≥ 5.76%).Texture parameters were selected by a stepwise linear discriminant analysis using IMF% measured by chemical extraction (IMFqa) as the dependent variable, and the results of the texture analysis as explanatory variables. 6 variables were found predictive and molded into a multiple regression equation, this equation was then validated using IMFqa as ground truth. A high linear correlation between IMFqa and IMFpred was evident (r2 = 0.8504), ROC analysis perfomed on IMFpred comparing it to IMFqa showed a sensitivity of 80% and a specificity of 93.7%, while results from the Bland-Altman plot were ± 1.96 (±1.11SD).

Fatty acid profiles of migrating female silver eel from Mediterranean coastal lagoons as integrative descriptors of spawners biological quality

The present study analyzed the lipid content and fatty acid profiles of European silver eels from Mediterranean lagoons, to interrogate the ecology and biology of eel, a panmictic species well represented in the region, with particular reference to breeder quality. Lagoons are coastal waterbodies included in transitional waters, sharing with these ecosystems, that include also brackish wetlands and river mouths, the characteristic of being influenced both by sea and continental waters. In the Mediterranean area these highly productive ecosystems, that also support a rich specific biodiversity, have a great relevance in relation to their great extent and the human and historical dimension, since they have long been exploited for their natural resources, especially for fishing. Eel collection was carried out in nine Italian lagoons typically representing these habitats, and two inland water habitats (a river and a lake) were added for comparison. Female silver eel muscle tissue revealed a mean lipid content significantly above the threshold considered necessary to provide the cue to trigger physiological reproductive changes for this species, in all the sampling sites irrespective of their typology. This emphasises the importance of Mediterranean coastal lagoons as habitats contributing to the eel oceanic migration, providing a significant share of spawning-stock biomass, both in terms of quality of the breeders and of their fitness to perform migration. Whereas the overall lipid content was similar among sites, the nine local populations differed in their fatty acid signatures. Thus, FA signatures might be proposed as integrative descriptors of eel spawner biological quality since they easily are able to differentiate among silver eel local stocks. Growth rates and body condition indices were strongly positively correlated to n-3:n-6 and DHA:EPA ratios in silver eels ready-to-migrate from the studied locations. This demonstrates that distinct PUFA, exclusively obtained through diet, are correlated with crucial biological features such as growth and condition of the silver eels that are going to undertake their journey to their oceanic reproduction sites. Overall, our results show the importance of additional tools for evaluating eel breeder quality that could also be integrated in the overall assessment of local stocks, a crucial step for ongoing and further management strategies of this endangered species.

Leaf Composition of American Bur-Reed (Sparganium americanum Nutt.) to Determine Pesticide Mitigation Capability.

American bur-reed (Sparganium americanum Nutt.), a common aquatic plant in the middle and eastern United States and Canada, is often located in water-retaining drainage areas. The purpose of this study was to determine the leaf composition of S. americanum, paying attention to the cuticular waxes and the epidermis, and its ability to sorb pesticides. S. americanum leaves (n = 100) were collected in both early (June) and late (August) summer. Transverse sections of S. americanum were stained and studied with brightfield and fluorescence microscopy to estimate the structural and chemical nature of the leaf tissues cross sections. Mean total lipid content in early summer leaf samples (1.47 ± 0.83mgmL-1) was significantly greater (alpha 0.05) than late summer leaves (0.15 ± 0.36mgmL-1). In vitro analysis of epidermal peel permeability exposed to atrazine and malathion determined little to no sorption by the plant. Therefore, the structure of S. americanum leaves suggest this species does not have the capacity of sorbing these pesticides from runoff water.

Effect of metabolites on stress, adaptation and longevity in laboratory populations of Drosophila flies

AbstractMetabolites like lipid and carbohydrate have significant roles on starvation, desiccation and longevity and differ in natural and laboratory populations of Drosophila. Five laboratory populations of Drosophila ananassae have been subjected to paraquat‐induced mortality and longevity, desiccation resistance, body size and ovariole number and tested for different metabolites (lipid, carbohydrate and water), fecundity and polymorphic chromosome inversions in each sex. Paraquat dose–response has clinal variation and means that paraquat mortality at different concentrations is significantly altered among males only. The overall mean ovariole number varies significantly (P ≪ 0.001) among different populations and one‐way ANOVA suggests significant variations (P ≪ 0.001) with mean fecundity and latitude. Only female longevity varies significantly among five different populations (P ≪ 0.001). Fecundity shows positive correlations with the longevity and suggests a possible role of different metabolites in keeping the cost effect. Two‐way ANOVA among mean water, lipid and carbohydrate contents in both sexes of different populations suggest significant differences among metabolites (P ≪ 0.001), between males and females (P ≪ 0.001, d.f. = 1) and for their interactions with each other (P ≪ 0.001) also. Significant differences are found for mean longevity, lipid and carbohydrate contents in both sexes of different populations in a two‐way ANOVA analysis (P ≪ 0.001), which suggests possible roles in their utilization at different levels during adaptation and stress. Longevity is affected significantly (P ≪ 0.001) by desiccation resistance also. Different chromosome inversions and their combinations show significant variations and sexual dimorphism with latitude and thorax length (P ≪ 0.001) and their roles are discussed in achieving adaptation, stress resistance and longevity.

Effects of Carbon Source on Growth Characteristics and Lipid Accumulation by Microalga <i>Dictyosphaerium</i> sp. with Potential for Biodiesel Production

Sustainability and eco-friendliness have both engendered research on alternative replacement of fossil fuel. This study was aimed at determining the effects of varying levels of glucose (10 ~ 40 g/L), and glycerol (0.25 ~ 1.0 mL/L) on the heterotrophic and mixotrophic growth and lipid production by Dictyosphaerium sp. The microalga was cultivated in 2000 mL amber-coloured bottles each containing 1000 mL of a sterile modified BG-11 medium at pH of 7.3. Each bottle was inoculated with a one-week-old pure culture of the isolate (inoculum ratio = 15%) and incubated in the dark at room temperature (30°C ± 2°C) for 10 d. Dictyosphaerium sp. showed the ability to grow heterotrophically and mixotrophically on glucose and on glycerol as a sole carbon substrates. Biomass productivity and specific growth rates did not vary when the initial medium glucose was varied. Lipid accumulation was not dependent on the initial medium glycerol contents. The mean lipid content and productivity of the organism in the present study were high enough to be utilised for industrial processes. Growth and lipid accumulations were better in mixotrophic cultures than both heterotrophic and autotrophic. However, both were better than autotrophic. The percentage compositions of the major fatty acids from Dictyosphaerium sp. grown under different culture conditions show at least five components each. The carbon skeletons eluted ranged from C14 to C22. Oleic acid was a major component of all the fatty acids, which confirm the suitability of the use of the oil for biodiesel production.

Growth performance and biochemical composition of the oysters Crassostrea sikamea , Crassostrea angulata and their hybrids in southern China

The Kumamoto oyster (Crassostrea sikamea) and the Portuguese oyster (C. angulata) are important aquaculture species which naturally coexist along the southern coast of China. To understand the potential feasibility of hybridization between the two species, we conducted two-by-two factorial cross-experiments in Beihai (Guangxi province), and also compared the survival and growth of the hybrids to that of the two parental progenies during the grow-out period from July 2014 to July 2015. Genetic analysis confirmed that the hybrid spats were true hybrids. Additionally, the biochemical composition of the 1-year-old oyster progenies was determined. In July 2015, the mean shell height of the hybrids was 42.98 ± 6.29 mm, which was higher than that of the Kumamoto oyster progeny. The cumulative survival rate of the hybrids was 26.37 ± 1.32%, which was higher than that of the progeny of the Portuguese oyster. Mean lipid content of the hybrids was 13.65 ± 1.63% of dry weight, which showed obvious heterosis compared to those of the two parental progenies. Observation of gonads revealed that all hybrids were completely fertile. Furthermore, relative expression of the lipid homeostasis genes, SREBP (sterol regulatory element-binding proteins), PPARα (peroxisome proliferator-activated receptor) and INSIG (insulin-induced gene) were found to vary between parental progenies and the hybrids, thus providing a possible reason for difference in the lipid contents of these experimental groups. Overall, the hybrids were viable, rich in lipid and completely fertile and thus could serve as a promising aquaculture stock for oyster breeding in southern China.

Effect of chlorfluazuron and flufenoxuron on development and reproductive performance of the black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae)

The black cutworm, Agrotis ipsilon, is an insect pest with great agricultural importance worldwide. In Egypt, it has acquired resistance against most of the conventional pesticides, particularly organophosphate insecticides, applied against it. Therefore, the present study aimed to investigate the effect of two benzoylureas (chitin synthesis inhibitors) namely chlorfluazuron and flufenoxuron on some developmental and reproductive parameters of Agrotis ipsilon that survived treatment of newly molted fourth instars with the LC50 of these compounds (1.00 and 4.68 mg/L, respectively) using leaf–dip method. These two compounds significantly enhanced the mean larval and pupal durations, whereas they significantly declined the mean percentage pupation, adult emergence, pupal weight, adult longevity, fecundity, and fertility compared to untreated insects. The mean pre-oviposition period was not significantly affected, whereas the mean oviposition period was significantly decreased. Both chlorfluazuron and flufenoxuron significantly decreased the mean total protein, carbohydrate, and lipid content in the ovaries compared to untreated insects, except for insignificant decrease in the total protein in flufenoxuron-treated ones. Additionally, the total ovariolar length was significantly atrophied. In conclusion, chlorfluazuron and flufenoxuron interfere with vitellogenesis of A. ipsilon. Moreover, they could suppress the population size of this insect species by affecting its development and reproductive potential.