Effects of dietary protein concentration and specific amino acids on body weight,body composition and feather growth in young turkeys

1. Two randomised block factorial experiments were conducted to investigate the relationships between the effects of dietary crude protein and specific amino acid concentrations on the relative growth of the body and feathers of young turkeys. 2. Decreasing dietary crude protein concentration from 300 to 180 g/kg in experiment 1 reduced the body and breast muscle weights of a large male line of turkeys proportionally by 0.44 and 0.52 compared with 0.19 and 0.24 in a small traditional line. 3. Decreasing dietary crude protein concentration was associated with a maximum reduction in feather weight of 0.18 and 0.24 respectively in male line and traditional turkeys. The length of the feathers in the cranial region of the breast decreased from 26 to 19mm in the traditional line compared with an increase from 14 to 25 mm in male line turkeys. 4. Decreasing dietary crude protein concentration was associated with an increase in the fat content of the feather-free carcase. Male line turkeys had a higher carcase fat and lower feather dry matter content than the traditional turkeys. 5. It was concluded that dietary crude protein was preferentially partitioned to feather rather than muscle growth in the male line in contrast to a traditional line of turkeys in which the growth of feathers and muscle were affected equally. 6. In experiment 2, the amino acids arginine, valine, methionine and tyrosine were added separately to a common basal ration (180g CP/kg) to raise their concentration to that of the control ration (260 g CP/kg). Each ration was fed ad libitum to male line turkeys from 2 to 6 weeks of age. 7. Amino acid supplementation increased body and breast muscle weights. 8. Compared with the basal ration, tyrosine was associated with a reduction in feather weight whereas valine had no effect. Supplementation with arginine and methionine resulted in increased feather weights that were similar to that of the controls. 9. It was concluded that arginine and methionine were used preferentially and are essential for feather growth. Excess amino acids that are not required for feather growth such as tyrosine and valine were used for increased body growth and resulted in relatively poor feather cover. 10. The results suggest that feather growth was maintained as much as possible at the expense of body growth when the amino acid concentration of the ration was less than that required to maximise body and muscle weight gain in large male line turkeys.     

Assessment of Selected Quality Parameters of Epididymal Cat (Felis catus s. domestica,L. 1758) Sperm Using Flow Cytometry Method and Computer Assisted Sperm Analyser

The improvement of biotechnical methods connected with fast and precise semen quality assessment and its utilization in assisted reproductive techniques is an urgent necessity in felids. The aim of this study was to evaluate some quality parameters (i.e. the viability and share of cells with intact plasma membrane) of epididymal sperm of cats using the flow cytometry method and computer‐assisted sperm analysis (CASA) examination. The material consisted of epididymal spermatozoa flushed from 22 pairs of epididymes after routine neutering procedures obtained from domestic cats aged between 8 and 36 months. The epididymes were cut and incubated with an extender without egg yolk. The samples were assessed for sperm viability (Live/Dead Sperm Viability Kit^®), percentage of subtle membrane changes (Apoptosis Detection Kit^®) and motility using FACScalibur flow cytometer and assisted sperm analyser htm ivos version 12.2. The flow cytometry method revealed 71.3% and 84.4% of live sperm using Live/Dead Sperm Viability Kit and Apoptosis Detection Kit respectively. The population of early‐apoptotic and late‐apoptotic sperm were 0.8% and 1.1% respectively. The CASA examination found 51.5% of motile sperm. However, the motility examination under light microscope revealed 69.5% of motile sperm. The data revealed an indistinctive per cent of apoptotic cells and 18.9% and 15.6% of dead cells using Live/Dead Sperm Viability Kit and Apoptosis Detection Kit, respectively, which indicate that the sperm obtained after flushing the epididymis possess potential properties for further assisted reproduction techniques.     

Changes in food intake and circulating leptin due to gastrointestinal parasitism in lambs of two breeds

A reduction in food intake is a prominent feature of many infectious diseases. However, the underlying mechanisms of parasite-induced anorexia in sheep are poorly understood. Here, we tested the hypotheses (a) that the degree of parasite-induced anorexia in lambs is influenced by their growth potential and (b) that nematode infection results in elevated plasma leptin concentration in lambs. The hypotheses were tested with Suffolk x Greyface (S) and Scottish Black-face (B) lambs that are known to differ in their growth potential (S lambs are of greater growth potential than B lambs). During a primary parasite infection, 24 out of 48 lambs per breed were trickle-infected with 7,000 infective Teladorsagia circumcincta larvae per day, 3 d/wk, for a period of 12 wk (experiment I). The lambs were then dewormed, and after a 2-wk interval, half of the 24 lambs per breed that were previously infected were reinfected for another 12 wk with the same parasite and dose as used in the primary infection (experiment II). In both experiments, infected lambs were fed grass pellets for ad libitum intake, whereas noninfected lambs were fed grass pellets for either ad libitum or restricted intakes. The S lambs were more susceptible than B lambs to nematode infection, as judged from the differences in fecal egg counts (P = 0.007). Parasitized lambs of the more susceptible breed (S) showed anorexia [i.e., a decrease in intake of 13% compared with uninfected controls (P = 0.01)], whereas no significant reduction in food intake was observed in lambs of the more resistant breed (B). Reexposure to nematode infection of previously infected animals tended to result in renewed anorexia in S lambs but not in B lambs (P = 0.08) in a similar extent as during primary infection. Plasma leptin concentrations did not differ between ad libitum-fed infected and control lambs but were greater in infected than in noninfected lambs at a similar level of food intake during both the primary (P = 0.02) and the secondary parasitic infection (P = 0.004) in both breeds. The results show that leptin may be involved in the response of lambs to infection but that it is unlikely that leptin alone is responsible for the parasite-induced anorexia in lambs.     

The Current State of Solar Modeling

Data from the Global Oscillation Network Group (GONG) project and other helioseismic experiments provide a test for models of stellar interiors and for the thermodynamic and radiative properties, on which the models depend, of matter under the extreme conditions found in the sun. Current models are in agreement with the helioseismic inferences, which suggests, for example, that the disagreement between the predicted and observed fluxes of neutrinos from the sun is not caused by errors in the models. However, the GONG data reveal subtle errors in the models, such as an excess in sound speed just beneath the convection zone. These discrepancies indicate effects that have so far not been correctly accounted for; for example, it is plausible that the sound-speed differences reflect weak mixing in stellar interiors, of potential importance to the overall evolution of stars and ultimately to estimates of the age of the galaxy based on stellar evolution calculations.