The essence of fertilization: oocyte meets sperm

The problem of reduced fertility in high yielding dairy cattle is a very complicated one, and the relationship between various measures of fertility and level of milk production remains controversial. In this brief review the essence of the problem is considered: what is the oocyte's and the sperm's contribution, and what is the importance of the resulting embryo in the declining fertility of the Holstein Friesian cow

Effect of sodium chloride concentration on the functional properties of selectec Legume flours

Providing safe, nutritious, and wholesome food for poor and undernourished populations has been a major challenge for developing countries. This has led to the necessity of assembling complete food composition tables, yielding information about the traditional foods and on the functional properties of the plant foods that are consumed regularly in the developing countries. Sodium Chloride (NaCl) is the common salt used at household and industry levels to improve palatability of processed foods. Therefore, the main aim of the present study was to investigate the influence of different concentrations of NaCl on the functional properties of selected legume flours. The effect of increasing concentration of NaCl on the protein solubility, emulsifying and foaming properties of white bean, pigeon pea, cowpea and hyacinth bean were studied. The results revealed that the protein solubility of pigeon pea, cowpea and white bean flours significantly increased by increasing salt concentration and reached a maximum at 0.4 M NaCl (for pigeon pea and cowpea flours) and 0.6 M for white bean flour and then gradually decreased at higher salt concentration. The protein solubility profile of hyacinth bean fluctuated with the salt concentration, with the highest solubility at 0.6 M NaCl and lowest solubility at 0.4M NaCl. With the exception of white bean, the maximum emulsifying activity of all selected legume flours was found at 0.4 M NaCl whereas that of white bean was found at 0.2 M NaCl. Generally, with increasing salt concentration, the emulsifying activity slightly decreased for the legume flours, except for cowpea which fluctuated. Addition of NaCl significantly decreased the emulsion stability and foaming capacity of the four of selected legume with the maximum improvement being observed at 0.2 M NaCl, and then decreasing gradually at higher salt concentration. Significant improvement of foaming stability was observed when salt concentration increased. Based on the results of the present study the selected legume flour demonstrated good functional properties following the addition of NaCl, which makes these legume flours potential ingredients for application in salt containing foods.Keywords: functional properties, Legumes, Protein solubilityAfrican Journal of Food, Agriculture, Nutrition and Development, Volume 12 No.

Detection of Trypanosoma brucei gambiense and T. b. rhodesiense in Glossina fuscipes fuscipes (Diptera: Glossinidae) and Stomoxys flies using the polymerase chain reaction (PCR) technique in southern Sudan

Ethanol-fixed entire bodies of the tsetse fly, Glossina fuscipes fuscipes, and unidentified stable flies, Stomoxys spp., collected from near Juba town, southern Sudan, were  tested for Trypanozoon trypanosomes infections using polymerase chain reaction (PCR) technique for the first time in Sudan. The crude target DNA sequences were extracted by incubation of entire flies in Nonindet PCR template buffer containing proteinase-K. The DNA amplification sets of conditions were adjusted for each pair of primers employed. The oligonucleotide primers used included TBR1-2, SRAA-E, SRAB537-B538 and TgsGPFOR-REV. The results showed that 74.4% of G. f. fuscipes and 39.36% of Stomoxys spp. were infected with Trypanozoon trypanosomes. Out of the 117 examined G. f. fuscipes, 46.2, 24.8, 35.04, 17.09 and 10.26% were due to T. b. gambiense (TgsGPFOR-REV), T. b. rhodesiense (SRAA-E), T. b. rhodesiense (SRA3537-3538), mixed infection with T. b. gambiense and T. b. rhodesiense and T. b. brucei, respectively. However, infections in Stomoxys spp. of 2.13 and 37.2% were due to T. b. rhodesiense and T. b. brucei, respectively.Key words: Glossina fuscipes fuscipes, T. b. gambiense, T. b. Rhodesiense, vectoral capacity, infection rate, PCR technology

Circadian rhythm of metabolic changes associated with summer heat stress in high-producing dairy cattle

The current study aimed to investigate the circadian rhythm of blood metabolic parameters associated with summer heat stress (HS) in dairy cows. Ten healthy lactating Holstein Friesian cows were followed during HS for three successive days at six different time points. Blood was sampled from each cow starting from 07:00AM; at 4-h intervals. Ambient air temperature and relative humidity were recorded, and temperature-humidity index (THI) was calculated as well. Respiration rate (RR) and rectal temperature (RT) were recorded for each cow at the time of blood sampling. Concentrations of glucose, non-esterified fatty acids (NEFA), total cholesterol (TC) and urea were measured in each blood sample. The THI values were >68 at all times of the day, and the highest values were recorded at 11:00AM, 03:00PM and 07:00PM (80.9, 83.7, and 80.8, respectively). All the cows showed a significantly higher RR and RT coinciding with higher THI values (93±4 and 39.6±0.1; 90.2±3.4, and 40.1±0.1; 87.6±4.1, and 39.8±0.1, respectively, P<0.05). The concentrations of glucose were the lowest at 11:00AM and 03:00PM (3.75±0.1 and 3.44±0.1 mmol/L, respectively, P<0.05). Decreased glucose concentrations coincided with increased NEFA concentrations, (0.43±0.01 and 0.56±0.02 mmol/L, respectively, P<0.05), and were highly negatively correlated (r=−0.50, P<0.001). The highest urea and TC concentrations were registered at 11:00AM (6.11±0.15 mmol/L and 109.9±2.2 mg/dl, respectively) whereas the lowest urea and TC values were recorded at 03:00AM (4.97±0.18 mmol/L and 99.5± 1.7 mg/dl, respectively, P<0.05). The results of the present study indicate that there was a circadian variation in glucose, NEFA, urea, and TC resulting in the most unfavorable metabolic condition during the hottest moment of the day in dairy cattle. Earlier work revealed that HS-metabolic changes are reflected in the follicular fluid. The circadian changes observed in the present study associated with HS may imply that also the microenvironment of the oocyte is affected

Vegetation and the importance of insecticide-treated target siting for control of Glossina fuscipes fuscipes

Control of tsetse flies using insecticide-treated targets is often hampered by vegetation re-growth and encroachment which obscures a target and renders it less effective. Potentially this is of particular concern for the newly developed small targets (0.25 high × 0.5 m wide) which show promise for cost-efficient control of Palpalis group tsetse flies. Consequently the performance of a small target was investigated for Glossina fuscipes fuscipes in Kenya, when the target was obscured following the placement of vegetation to simulate various degrees of natural bush encroachment. Catches decreased significantly only when the target was obscured by more than 80%. Even if a small target is underneath a very low overhanging bush (0.5 m above ground), the numbers of G. f. fuscipes decreased by only about 30% compared to a target in the open. We show that the efficiency of the small targets, even in small (1 m diameter) clearings, is largely uncompromised by vegetation re-growth because G. f. fuscipes readily enter between and under vegetation. The essential characteristic is that there should be some openings between vegetation. This implies that for this important vector of HAT, and possibly other Palpalis group flies, a smaller initial clearance zone around targets can be made and longer interval between site maintenance visits is possible both of which will result in cost savings for large scale operations. We also investigated and discuss other site features e.g. large solid objects and position in relation to the water's edge in terms of the efficacy of the small targets

How do tsetse recognise their hosts? The role of shape in the responses of tsetse (Glossina fuscipes and G. palpalis) to artificial hosts

Palpalis-group tsetse, particularly the subspecies of Glossina palpalis and G. fuscipes, are the most important transmitters of human African trypanomiasis (HAT), transmitting .95% of cases. Traps and insecticide-treated targets are used to control tsetse but more cost-effective baits might be developed through a better understanding of the fly’s host-seeking behaviour.Electrocuting grids were used to assess the numbers of G. palpalis palpalis and G. fuscipes quanzensis attracted to and landing on square or oblong targets of black cloth varying in size from 0.01 m2 to 1.0 m2. For both species, increasing the size of a square target from 0.01 m2 (dimensions = 0.1 x 0.1 m) to 1.0 m2 (1.0 x 1.0 m) increased the catch ,4x however the numbers of tsetse killed per unit area of target declined with target size suggesting that the most cost efficient targets are not the largest. For G. f. quanzensis, horizontal oblongs, (1 m wide x 0.5 m high) caught, 1.8x more tsetse than vertical ones (0.5 m wide x 1.0 m high) but the opposite applied for G. p. palpalis. Shape preference was consistent over the range of target sizes. For G. p. palpalis square targets caught as many tsetse as the oblong; while the evidence is less strong the same appears to apply to G. f. quanzensis. The results suggest that targets used to control G. p. palpalis and G. f. quanzensis should be square, and that the most cost-effective designs, as judged by the numbers of tsetse caught per area of target, are likely to be in the region of 0.25 x 0.25 m2. The preference of G. p. palpalis for vertical oblongs is unique amongst tsetse species, and it is suggested that this response might be related to its anthropophagic behaviour and hence importance as a vector of HAT

Optimizing the colour and fabric of targets for the control of the tsetse fly Glossina fuscipes fuscipes

Background: Most cases of human African trypanosomiasis (HAT) start with a bite from one of the subspecies of Glossina fuscipes. Tsetse use a range of olfactory and visual stimuli to locate their hosts and this response can be exploited to lure tsetse to insecticide-treated targets thereby reducing transmission. To provide a rational basis for cost-effective designs of target, we undertook studies to identify the optimal target colour. Methodology/Principal Findings: On the Chamaunga islands of Lake Victoria , Kenya, studies were made of the numbers of G. fuscipes fuscipes attracted to targets consisting of a panel (25 cm square) of various coloured fabrics flanked by a panel (also 25 cm square) of fine black netting. Both panels were covered with an electrocuting grid to catch tsetse as they contacted the target. The reflectances of the 37 different-coloured cloth panels utilised in the study were measured spectrophotometrically. Catch was positively correlated with percentage reflectance at the blue (460 nm) wavelength and negatively correlated with reflectance at UV (360 nm) and green (520 nm) wavelengths. The best target was subjectively blue, with percentage reflectances of 3%, 29%, and 20% at 360 nm, 460 nm and 520 nm respectively. The worst target was also, subjectively, blue, but with high reflectances at UV (35% reflectance at 360 nm) wavelengths as well as blue (36% reflectance at 460 nm); the best low UV-reflecting blue caught 3× more tsetse than the high UV-reflecting blue. Conclusions/Significance: Insecticide-treated targets to control G. f. fuscipes should be blue with low reflectance in both the UV and green bands of the spectrum. Targets that are subjectively blue will perform poorly if they also reflect UV strongly. The selection of fabrics for targets should be guided by spectral analysis of the cloth across both the spectrum visible to humans and the UV region

Improving the Cost-Effectiveness of Artificial Visual Baits for Controlling the Tsetse Fly Glossina fuscipes fuscipes

Tsetse flies, which transmit sleeping sickness to humans and nagana to cattle, are commonly controlled by stationary artificial baits consisting of traps or insecticide-treated screens known as targets. In Kenya the use of electrocuting sampling devices showed that the numbers of Glossina fuscipes fuscipes (Newstead) visiting a biconical trap were nearly double those visiting a black target of 100 cm×100 cm. However, only 40% of the males and 21% of the females entered the trap, whereas 71% and 34%, respectively, alighted on the target. The greater number visiting the trap appeared to be due to its being largely blue, rather than being three-dimensional or raised above the ground. Through a series of variations of target design we show that a blue-and-black panel of cloth (0.06 m2) flanked by a panel (0.06 m2) of fine black netting, placed at ground level, would be about ten times more cost-effective than traps or large targets in control campaigns. This finding has important implications for controlling all subspecies of G. fuscipes, which are currently responsible for more than 90% of sleeping sickness cases