Generalized biomass equations for the main aboveground biomass components of maritime pine across contrasting environments

• Introduction   

In order to predict the biomass of aerial components of maritime pine stands (Pinus pinaster Ait.), generalized allometric equations were developed using data collected from the southern and northern margins of its geographical area.     

Isolation and identification of locally isolated bacterial strains effective against whitefly Bemisia tabaci

Potent bacterial strains effective against the whitefly, Bemisia tabaci, nymphs (second instar), were isolated from tomato cultivated fields at Fayoum governorate, Giza, Egypt. Of 72 isolates, 12 with the most morphologically distinct-looking bacterial colonies were selected and named A1, A2, A3, A6, A7, A9, A12, A13, A107, B37, B45 and B100. All isolates were preliminarily identified as members of the genus Bacillus based on morphological, physiological and biochemical characteristics. When tested for their pathogenicity against Bemisia tabaci, the 12 isolates revealed varying efficiencies with isolates A1 and A9 being superior, exhibiting maximum mortality of 92.2 and 90.8% on day 10, respectively. Isolate A7 recorded the lowest percentage at 18.3%. Further genetic characterization of the 12 isolates was performed using inter simple sequence repeat (ISSR), randomly amplified polymorphic DNA (RAPD) and 16S rDNA gene sequencing analysis. RAPD and ISSR results confirmed each other. The combined ISSR and RAPD phylogenetic tree showed two major clusters. With 16S rRNA gene analysis, isolate A1 and A12 sequences recorded 100% identity with Bacillus thuringiensis, while isolates A7 and B100 showed 95.7% and 95.6% identity with Bacillus cereus and Bacillus sphaericus, respectively.     

Effects of Zn2+ on Ca2+ uptake by mitochondria and endoplasmic reticulum in permeabilized tilapia gill cells

An intracellular ATP-dependent Ca²⁺ pumping mechanism, distinct from mitochondrial Ca²⁺ accumulation, was identified within tilapia gill cells. Cell suspensions treated with 0.003% saponin, which selectively permeabilizes the plasma membrane, were used to characterize the Ca²⁺ sequentering mechanisms as endoplasmic reticulum and mitochondria and to determine the effect of Zn²⁺ on their Ca²⁺ storing activity. Of the Ca²⁺ taken up by the endoplasmic reticulum, 80% was released by IP₃ (10 mol l^–1). The Ca²⁺ pump of the endoplasmic reticulum was 2.5 times less sensitive to Zn²⁺ (IC₅₀=0.05 nmol l^–1) than was the mitochondrial uptake mechanism (IC₅₀=0.20 nmol l^–1). The results indicate that Ca²⁺ is stored predominantly within the endoplasmic reticulum at 0.1 mol l^–1 and that this storing capacity is seriously attenuated by namomolar concentrations Zn²⁺.     

Exploring the impacts of different fasting and refeeding regimes on Nile tilapia (Oreochromis niloticus L.): growth performance,histopathological study,and expression levels of some muscle growth-related genes

Fish Physiology and Biochemistry - The current study investigated how different fasting and refeeding regimes would impact Nile tilapia growth performance, histopathological examination, and gene...     

Effect of Garlic,Echinacea, Organic Green and Vet-Yeast on Survival,Weight Gain,and Bacterial Challenge of Overwintered Nile Tilapia Fry (Orechromis niloticus)

The purpose of this study was to examine the effect of some immunostimulants and probiotics on the survival rate, final weight, and disease resistance of overwintered tilapia fry. There were five treatments: T1 (control) fed a balanced diet (35% protein) without additives. Treatments 2 to 5 were fed diets supplemented with 4% garlic, 4 g/kg Echinacea, 4 g/kg Organic Green or 4 g/kg Vet-Yeast, respectively. Growth and resistance to disease challenge with Aeromonas hydrophila and Pseudomonas flourescens were not different among treatments, but survival of overwintered fry increased in treatments fed probiotics or immunostimulents. The use of garlic in overwintering feeds could allow hatchery operators to increase their prices for fry and fish farmers to stock production ponds earlier, increasing hatchery revenues by 74% and improving land use efficiency and productivity for the Egyptian aquaculture industry.     

Growth performance,oxidative stress indices and hepatic carbohydrate metabolic enzymes activities of juvenile Nile tilapia,Oreochromis niloticus L., in response to dietary starch to protein ratios

The effect of various dietary starch to proteins ratios (STA/P) on growth performance, oxidative status and liver enzyme activities involved in intermediary metabolism in juvenile Nile tilapia was evaluated. Four isocaloric‐practical diets (12.73 MJ kg^?1 digestible energy) with increasing STA/CP ratios were formulated. These were designated D₀ (344 g crude protein (CP) and 163.5 g starch (STA) kg^?1), D₁ (310 g CP and 243 g STA kg^?1), D₂ (258 g CP and 322 g STA kg^?1) and D₃ (214 g CP and 401 g STA kg^?1). Each diet was fed to triplicate groups of 60 fish (2.7 g) for 45 days. Compared with the control diet (D₀), significantly (P < 0.05) depressed growth and feed efficiency were observed only in the groups fed on diet D₃. The activities of hepatic enzymes involved in glycolysis and lipogenesis pathways were significantly enhanced in groups fed on diet D₃ compared with other diets. A significant (P < 0.05) increase in catalase activity was detected only in groups fed on diet D₃. Similarly, a significant (P < 0.05) enhancement in superoxyde dismutase, glutathione S‐transferases and glutathione peroxidise was observed in groups fed on diets D₂ and D₃ compared with other diets. Results demonstrate the ability of juvenile Nile tilapia to spare protein by dietary carbohydrate.     

Assessment of Biotransformation of Sludge from Vegetable Oil Refining by Composting

The evolution of organic matter of sludge from vegetable oil refining (50%) mixed with turf (40%) and straw (10%) during 6 months of composting was evaluated by physicochemical and spectroscopy analysis. The intense microbial activity is characterized by a significant increase in temperature (over 67°C) during the thermophilic phase (7 days). The final product is characterized by a decomposition rate of 50, C/N ratio about 12, NH₄⁺/NO₃^? ratio less than 1, and a neutral pH. The lipid analysis showed that total lipids decreased by 83% as a result of biodegradation of lipid compounds of the composted substrate. The degree of polymerization during composting is of about 16%, which provides information on the success of the process. The spectroscopic analysis showed a decrease of the ratios E4/E6 and E2/E6, which clearly shows the humification of organic matter. The physicochemical and spectroscopy parameters of the mixture show the stability and maturity of the final compost, which is confirmed by the germination index (60% for lettuce and turnips, and 90% for cress and lucerna). The results of the evolution of sludge from vegetable oil refining mixed with green wastes produced a mature product that can be applied in agriculture.     

Effect of a probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid‐induced colitis in rats

This study aimed to investigate the potential effects of an oral treatment by a newly isolated probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid (TNBS)‐induced colitis in Wistar rats. Thus, 18 rats were divided into three groups (n = 6 per group): group 1 (control) – rats not receiving TNBS application; group 2 – rats receiving an intrarectal TNBS infusion (100 mg/kg TNBS dissolved in ethanol); and group 3 – rats treated with intragastrical TN8 strain once per day (for 5 days before TNBS induction). The performance and the effects of the probiotic treatment were evaluated using a series of histological, biophysical and biochemical analyses. The results have shown that the treatment with the L. plantarum TN8 strain improves the body weight and reduces the diarrhoea, colonic mucosal inflammation and colon shortening. TN8‐treated rats showed a significant decrease in the total cholesterol content from 1.86 (for group 2) to 1.32 mmol/l and in triglyceride (TG) content from 2.09 (for group 2) to 1.23 mmol/l. Furthermore, the findings revealed that the high‐density lipoprotein (HDL) cholesterol contents increased from 0.95 to 1.02 mmol/l. The histological studies have confirmed that the architecture of the liver and kidney tissues of the TN8‐treated rats were found to be improved. Overall, the results suggest that the L. plantarum TN8 presents promising perspectives for the development of safe and cost‐effective agents for the prevention or alleviation of several intestinal pathologies.