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This study investigated the effects of dietary Syzygium aromaticum supplementation on egg qualities, egg cholesterol and reproductive morphometry of laying hens. Three experimental diets were formulated containing 0.00%, 0.25% and 0.50% Syzygium aromaticum leaf meal (SLM). One hundred and fifty (20 weeks old) Isa-Brown birds were randomly assigned to three-treatment group which comprised 50 birds replicated five times with 10 birds each. Six eggs were collected from each replicate three days to the end of the 1st cycle of laying (4 weeks), 2nd and 3rd cycles and properly labelled for egg qualities assessment. At the end of the 12 weeks feeding trial, 45 birds (3 birds per replicate, that is, 15 birds per treatment) were slaughtered and dissected to evaluate their reproductive parameters. The result showed positive dietary effect (P<0.05) on shell thickness, yolk height, yolk index and egg mass. Cholesterol level of whole eggs, egg yolk and albumen were significantly lowered. Weight of entire reproductive tract and ovary as well as length of infundibulum, magnum, isthmus, uterus and vagina were significantly increased by dietary SLM. Conclusively, clove supplementation at 0.25% and 0.50% could be adopted for improved egg shell thickness and low-cholesterol eggs in poultry production

Background Performance of rabbit is hinged on many factors of which the birth weights, gestation length and the litter size are most important. Linear body traits provide vital information on the performance, productivity and carcass characteristics which could be useful tool for the improvement in genetic potentials of rabbits. Therefore, this study investigated the effects of genotype, gestation length and litter size on the birth weight, pre- and post-weaning weight of crossbred kits. Results Five breeds: Rex (RX), Dutch-belted (DBT), New Zealand white (NZW), Californian white (CFW) and local breed (LAB) of rabbit were used for the study. A foundation stock of 40 growing rabbits consisting of six does and two bucks were used for the crossing experiment. Genotype exerted significant influence (P < 0.01) on the litter weight at birth as well as on the body weight of the kits at 21st and 35th days. The kit kindled from mating CFWxDBT breeds had the highest mean body weight from birth (91.90 ± 9.84 g) to 35th days (368.25 ± 17.36 g), while the crosses of DBTxCFW recorded the least mean body weight from birth (74.25 ± 1.78 g) to 35th days (332.60 ± 12.54 g). Gestation length significantly (P < 0.05) influenced individual and litter birth weights, pre- and post-weaning weights of kits. Does with short gestation length (29 days) had kits with light body weight compared to those with longer period of gestation (34 days). More so, kits belonging to large litter size (7) had the lowest body weight at birth as well as 21st and 35th day (69.93 ± 1.63 g, 209.57 ± 3.70 g, 319.11 ± 9.22 g) compared to kits that belonged to small litter group size. Highly significant (P < 0.01) and the strongest phenotypic relationships were recorded between body weight at day 21 and day 35 for all crosses, while weak and negative genetic correlation (r =  − 0.19) was observed between litter birth weight and individual birth weight of crossbred kits. Conclusion Crossbreeding produces offspring with better performances. Birth weight of kits is a prediction tool for the overall performance of rabbits provided the environment is uninterrupted.

Background The study examined the effects of dietary supplementation of Syzygium aromaticum leaf meal (SLM) on the haematology, serum biochemistry and antioxidative status of laying hens. Results A total of 150 20-week-old Isa brown birds were randomly assigned to three experimental diets: Diet 1/control (no supplementation), Diet 2 (0.25% SLM) and Diet 3 (0.50% SLM). Each experimental diet was further divided into five (5) replicates and comprised 10 birds per replicate, that is, 50 birds per experimental diet. The birds were fed with layers mash for 32 weeks of the feeding trial. Blood samples collected in the 32nd week were subjected to haematological and serum biochemical analyses. The dietary supplementation of 0.25% and 0.50% SLM did not significantly (P > 0.05) affect the haematological parameters observed in the layer birds which indicated that SLM did not render the birds anaemic nor compromise their immunity. Likewise, the result of the serum protein (total protein, albumin, globulin and albumin: globulin), serum enzymes (alanine and aspartate aminotransferases) and serum metabolites (creatinine, uric acid and glucose) were not affected (P > 0.05) by the dietary treatment except for the concentration of serum catalase and glutathione peroxidase which was statistically higher (P < 0.05) in layers fed with diets supplemented with SLM compared to the control group, while the serum superoxide dismutase concentration of laying hens was not significantly influenced (P > 0.05). Conclusion The supplementation of SLM at 0.25% and 0.50% in layers diet can be referred to as a safe additive as the blood indices of birds were not adversely affected. Also, the liver functions which were investigated through the serum enzymes were not impaired and oxidative stress is not triggered in the birds.