Seasonal effects on semen quality in Black Baladi and White New Zealand rabbit

[EN] A total of 32 sexually mature rabbit bucks (at 6th month of age) were used in this experiment to study the effects of breed (Black Baladi -BB- vs. White New Zealand -WNZ-) and season (summer vs. winter) on libido and seminal parameters. The experimental design was completely random with four groups arranged factorially (two breeds and two seasons) with eight rabbits in each group and three months per season. The results obtained from this study indicated that, libido (14.5 vs. 21.9 sec) and physical semen characteristics represented by the volume of semen per ejaculate without gel fractions (0.70 vs. 0.49 mL), sperm-cell concentration (703 vs. 597¿106/mL), total sperm output (513 vs. 293¿106/ejaculate), sperm abnormalities (11.6 vs. 14.0%), acrosomal damages (8.6 vs. 11.5%), dead spermatozoa (13.9 vs. 16.0%), and advanced sperm motility (63.2 vs. 57.1%) were signifi cantly (P<0.01) better on BB rabbit bucks than on WNZ breed. In addition, these parameters proved to be signifi cantly (P<0.01) better in winter season (15.8 sec, 0.68 mL, 702¿106/mL, 487¿106/ejaculate, 10.7%, 8.4%, 12.7%, and 65.6%, respectively) than in summer (20.6 sec, 0.52 mL, 598¿106/mL, 319¿106/ejaculate, 15.0%, 11.7%, 17.3%, and 54.7%, respectively). Following the hypo-osmotic swelling test (HOST) at 75 mOsmol/L during incubation at 37oC for 20 min, the percentages of sperm motility, swollen spermatozoa, and spermatozoa with coiled tails were higher for BB bucks (16.98, 44.08, and 39.13) than for the WNZ breed (7.2, 32.3, and 26.0). This was also the case in the winter season (14.4, 42.7, and 38.5) when compared to summer (9.8, 33.7, and 26.6), respectively. We concluded that, under Egyptian conditions, both libido and semen quality in BB bucks seems to be better than those displayed by the WNZ bucks. Nevertheless, overall semen characteristics were better in winter than in the summer season.Safaa, H.; Emarah, M.; Saleh, N. (2010). Seasonal effects on semen quality in Black Baladi and White New Zealand rabbit. World Rabbit Science. 16(1). doi:10.4995/wrs.2008.64016

Semen evaluation of two selected lines of rabbit bucks

[EN] Twenty rabbit bucks of 9 months of age were used to evaluate semen quality of two lines of New Zealand rabbit bucks selected for litter size at weaning (A line) and growth rate from weaning to slaughter (R line). The morphological semen characteristics indicated that the A line spermatozoa had greater acrosome integrity (+3.6 percentage units; P<0.01) and smaller sperm head size (for example, ¿1.46 ¿m2 for sperm head area) than in the R line. Seminal functional traits were also significantly higher for the A line (+13.4 percentage units for viability, +10.6 percentage units for hypo-osmotic swelling test (HOST) and +3.3 g/L for seminal plasma protein. However, no differences were detected between lines for motility parameters and seminal plasma protein electrophoretic profiles. Both lines had the same twelve bands with the following molecular weights to the nearest 1 kD: 124, 117, 99, 86, 75, 62, 40, 32, 21, 19, 10 and 6 kD. A relationship (r=0.308 for A line and 0.359 for R line; P<0.01) was found between the integrity of the plasmatic membrane (viability rate) and tail membrane (HOST) of the spermatozoa in the A line, but not in the R line, which had greater sperm head size. There was also a significant positive correlation coefficient between sperm concentration and either viability or some kinetic traits (r=0.567 and 0.575 for VCL, r=0.584 and 0.561 for VSL and r=0.588 and 0.588 for VAP, for A and R lines, respectively; P<0.001). We concluded that the A line seems to have better semen characteristics than the R line. We also found an interesting correlation among the seminal morphological, functional and kinetic traits, which could possibly be used to facilitate semen evaluation.Hosam M. Safaa was supported by a grant from ICSC-World Laboratory, Switzerland. This work has been supported by the Spanish Research Project (CICYT AGL2004-02710/GAN). The authors are indebted to F. Marco-Jiménez, Universidad Politécnica de Valencia, Valencia, Spain, and G.M.K. Mehaisen, Department of Animal Production, Faculty of Agricultural, Cairo University, Giza, Egypt, for their excellent cooperation throughout this study and to D.A.A. El-Sayed, Faculty of Agricultural, Cairo University, Giza, Egypt, for her help in preparing the manuscript.Safaa, H.; Vicente, J.; Lavara, R.; Viudes De Castro, M. (2008). Semen evaluation of two selected lines of rabbit bucks. World Rabbit Science. 16(3). doi:10.4995/wrs.2008.62216

Influence of the Main Cereal and Feed Form of the Diet on Performance and Digestive Tract Traits of Brown-Egg Laying Pullets.

The influence of the main cereal and feed form of the diet on performance and digestive tract traits was studied in 576 brown-egg laying pullets from 1 to 120 d of age. From 1 to 45 d of age, 4 diets arranged factorially with 2 cereals (corn vs. wheat) and 2 feed forms (mash vs. pellets) were used. Each treatment was replicated 6 times (24 pullets per replicate). From 46 to 120 d of age, all diets were offered in mash form and the only difference among diets was the cereal used. Cumulatively, pullets fed the corn diets had higher BW gain (P < 0.05) but similar feed conversion ratio as pullets fed the wheat diets. From 1 to 45 d of age, pullets fed pellets consumed more feed (P < 0.001) and had higher BW gain (P < 0.001) than those fed mash. Most of the beneficial effects of pelleting on productive performance were still evident at 120 d of age. At 45 d of age, gizzard weight (g/kg of BW) was higher (P < 0.01) in pullets fed corn than in pullets fed wheat diets. Feeding pellets reduced the relative weight of the digestive tract and the gizzard (P < 0.001) as well as the length (cm/kg of BW) of the small intestine (P < 0.01) at both ages. The pH of gizzard contents at 120 d of age was not affected by cereal but was lower in pullets that were fed mash from 1 to 45 d of age (P < 0.01). We conclude that wheat can be used in substitution of corn in pullet diets with only a slight reduction in BW gain and that feeding pellets from 1 to 45 d of age increased BW gain and pH of the gizzard and reduced the relative weight of the gizzard and the length of the gastrointestinal tract at 120 d of age

Nutritional levels of digestible methionine + cystine to brown-egg laying hens from 50 to 66 weeks of age

The objective of this study was to determine the requirement of digestible methionine + cystine of brown-eggs laying hens from 50 to 66 weeks age at the end of the first production cycle. The design was completely randomized, with 150 Brown Shaver hens, which were distributed in five treatments with six replications of five birds each. Birds received a basal diet with 2857 kcal/kg metabolizable energy and 15.97% crude protein, supplemented with 0.132; 0.174, 0.215, 0.256 and 0.298% DL-methionine (98%), in order to provide 0.572, 0.613, 0.653, 0.693 and 0.734% digestible methionine + cystine. The levels of digestible methionine + digestible cystine followed, respectively, the relations of 67, 72, 77, 81 and 86% with lysine fixed at 0.851%. Feed intake, methionine + cystine intake, feed conversion per dozen eggs, egg weigth and mass, percentage of egg components, internal egg quality and weight gain were evaluated. Methionine + cystine levels showed a quadratic effect on feed conversion per dozen eggs and egg weight, a linear effect on feed conversion per kilogram of eggs and percentage of albumen. There was also a positive linear effect on yolk percentage. The methionine + cystine requirement was estimated at 0.572%, corresponding to 682 mg of digestible methionine + cystine/bird/day