Growth performance, carcass quality, biochemical and haematological traits and immune response of growing rabbits as affected by different growth promoters.

The aim of the article was to study the effect of different growth promoters on growth performance, carcass quality, biochemical and haematological traits and immune response of growing rabbits. A total number of 105 male growing NZW rabbits during 35-91 days of age were randomly distributed among 7 groups fed the same basal diet and submitted to different dietary treatments: the first group was unsupplemented and used as control; the other groups were supplemented respectively with bee pollen and/or propolis at 200 mg/kg BW of each and inulin and/or mannanoligosaccharides (MOS) at 35 mg/kg BW of each. Body weight gain, daily feed intake, feed conversion ratio (FCR), biochemical and haematological blood parameters, carcass characteristics, histological studies of ileum and spleen and economical efficiency were measured. Bee pollen administered alone or with propolis significantly (p < 0.01) the body weight gain and improved FCR in respect of the control group. Inulin with MOS significantly improved just FCR than the control group. Bee pollen with propolis and MOS supplemented-groups resulted in significantly higher (7.96 and 8.41% respectively) white blood cells compared to the control group. Plasma total cholesterol was significantly higher for the MOS group in respect of the control, bee pollen, inulin and inulin with MOS supplemented-groups. Propolis resulted in significantly higher dressed carcass percentage than the control group and higher carcass index than only bee pollen with propolis supplemented-group. Bee pollen, in particular if in combination with propolis, could be used as a supplement in the growing rabbits during days 35-91 of age with positive effects on growth rate and feed conversion ratio.

Effect of incubation humidity and flock age on hatchability traits and posthatch growth in Pekin ducks.

This study was conducted to determine the effect of incubation relative humidity (RH) from 14 to 24 d of incubation during 3 parental ages on hatchability and posthatching growth of Pekin ducklings. Egg production was divided into 3 age groups (25-35, 36-55, and 56-65 wk). A total of 21,600 hatching eggs was subjected to 55, 60, 65, and 70% RH from 14 to 24 d, whereas standard conditions were used from 0 to 14 d and 24 to 28 d of incubation. All eggs were individually weighed before setting in the incubator and again at 14 and 24 d of incubation to determine egg weight loss. A sample of 20 eggs from unhatched and hatched eggs from each group were randomly taken on the hatching day and used to determine eggshell thickness and pore number. Duckling weight at hatching was recorded and BW gain, feed consumption, feed conversion, and viability were then recorded to 21 d of age. Egg weight increased with hen age but did not differ by incubation treatment. Increasing RH from 55% to 60, 65, and 70% decreased percentage egg weight loss in a stepwise manner irrespective of parental age. Shell thickness was less for hatched eggs compared with nonhatched eggs within each parental age. Shell thickness decreased while pore density increased with increased parental age for both nonhatched and hatched eggs. The lowest embryonic mortality among the incubation periods (14-24 and 0-24 d) and best hatchability of fertile eggs was recorded with 60% RH during the first parental age (25-35 wk), 65% RH during 36-55 wk of age, and 70% RH during 56-65 wk of age. The best incubation results were directly associated with the greatest duckling BW at hatching and at 21 d of age, BW gain, feed conversion, and viability during each parental age period. It was concluded that duck eggs produced within a specific parental age period require a specific incubation RH to attain the best hatchability and posthatching duckling performance.

Effect of different managerial systems on productive and reproductive traits, blood plasma hormones and serum biochemical constituents of geese.

A flock of 117, 10-month-old Egyptian geese consisting of 90 females and 27 males were utilized in this investigation. Birds were randomly divided into three equal groups, each made up of three replicates of 10 females and 3 males each. The first group was kept under a pasture system (PS) and allowed to swim in water ducts during the daytime (PS) and kept inside the house during the night. The second group of birds were kept in confinement in a house and fed ad libitum on a commercial feed (intensive system (IS)). Birds in the third group (semi-intensive system (SIS)) were released from the house for 6 h a day and given access to the pasture and water ducts. Each group was housed in three pens (replicates) in the SIS. They were given ad libitum access to the commercial feed when in the house. Each pen measured (2 × 3 m2). Natural mating was practiced during the period from November to the end of May. BW of geese under ISS was significantly (P ⩽ 0.05) higher than those under PS and SIS. Egg number, weight and mass of geese in the SIS system were significantly (P ⩽ 0.05) greater than those of geese in the PS and IS systems. Fertility and hatchability percentages were significantly (P ⩽ 0.05) greater in the PS (84.2% and 88.6%) than in the IS (77.5% and 82.8%) and SIS systems (80.7% and 85.5%). Shell weight and thickness were significantly (P ⩽ 0.05) better in the IS and SIS systems than in the PS system. Geese in the PS and SIS systems exhibited significantly higher plasma estradiol-17 and progesterone than those in the IS. Testosterone was significantly higher in IS than in the other systems. Semen quality factor was significantly higher in the PS and SIS systems than in the IS system. Carcass weight was significantly greater in IS and SIS geese than in PS geese, but the PS system resulted in a decreased percentage skin, abdominal fat and liver. Total amount of meat produced per geese was significantly greater in the SIS than in the IS system and greater in the IS than in the PS system.