Tibia properties in broilers raised on their own commercial diets with different growth rates and sex during a 10-week rearing period.

BACKGROUND: Genetic selection applied to broilers results in fast growth and an increase in meat yield. However, this situation causes welfare problems in broilers. OBJECTIVES: The aim of this study is to determine the weekly changes in the tibia characteristics in broilers raised on their own commercial diets. METHODS: In the study, 168 (84 female and 84 male) slow-growing (Hubbard-Isa Red JA) and 168 (84 female and 84 male) fast-growing (Ross-308) day-old broiler chicks were used. Six broilers from each genotype and sex group were weighed weekly and slaughtered to determine the tibia properties during the 10-week fattening period. RESULTS: Fast-growing broilers had higher tibia weight and longer length, diaphysis diameter and medullary canal diameter than those of slow-growing broilers at the same age. In fast-growing genotypes, the cortical index was low only in the 2nd week, and Robusticity and Seedor indices were observed to be better throughout the whole fattening. The ash content of the total tibia in the fast-growing broilers was higher in all of the examined weeks except the 4th week and the 9th week of fattening than that in the slow-growing broilers. Although the amount of ash per unit body weight in the 1st week of fattening was higher in fast-growing broilers, this situation reversed after the 4th week. The level of all minerals examined in total tibia weight is high in fast-growing broilers, and they differed according to the fattening period. CONCLUSIONS: When comparing tibia characteristics of two different genotypes fed their own commercial diets, the tibia structure was found to be stronger in fast-growing broilers compared to other genotypes at the same age, but slow-growing broilers were more prominent in terms of body weight. It was observed that the mineral density was higher in male broilers, except in the 1st week.

Age and sex related changes in fattening performance, dermatitis, intestinal histomorphology, and serum IgG level of slow- and fast-growing broilers under the intensive system.

Due to consumers' concerns about broiler welfare, slow-growing broilers (SGB) have also been used in production. Fast-growing broilers (FGB) reach slaughter weight earlier the slow growing. This study was aimed to determine the sex-related changes in fattening performance, dermatitis, intestinal histomorphology, and serum IgG level of SGB and FGB under the intensive system during the 10 weeks. A total of 336 one-day-old broilers were distributed into four equal groups (FGB-female, FGB-male, SGB-female, and SGB-male) consisting of a 2 × 2 factorial design. The main factors were genotype (FGB and SGB) and sex (female and male). Each treatment had 6 duplicates consisting of 14 broilers. They were placed on the litter pens. The experiment lasted 10 weeks. The body weight, body weight gain, feed consumption, and feed-to-gain ratio were determined weekly during the experiment. One broiler close to the average body weight from each pen (6 broilers in the group) has been slaughtered each week and intestinal histomorphology was determined. Additionally, IgG levels in the blood and dermatitis were determined. While the period in which the body weight gain was the highest in the FGB was up to 6 week of age, this period lasted until the 7 week of age in the SGB (P < 0.001). It has been determined that FGB have the best feed efficiency ability during both 6 weeks of fattening period and 10 weeks of fattening period (P < 0.001). The difference between the sex in terms of the feed efficiency appeared after the age of 4 weeks and this difference continued until the age of 9 weeks (P < 0.01). It was determined that villus height, crypt depth, and the ratio of villus height to crypt depth in the jejunum region were higher in FGB from the age of 1 week than in SGB (P < 0.05). It was observed that the incidence of dermatitis increased in the FGB (P < 0.001). It has been determined that the genotype (P < 0.01) and period (P < 0.001) were effective according to the IgG level. These results indicate that 7 and 8 weeks can be considered important periods in terms of economic efficiency in SGB and FGB reared for 10 weeks under the same management systems and it was observed that both genotypes would be more susceptible to diseases at the age of 6 weeks.

Effects of the genotype, cage type and time period on the behaviour of laying hybrids at the same egg production level.

Hybrids with different morphological and yield characteristics are used in the table egg production. There is no change in the cage systems according to the different hybrids in the regulation. This study aimed to investigate the effects of genotype (brown laying hybrids (BLH) and white laying hybrids (WLH)) and cage type (conventional and enriched cages) on behaviours of hens at the 90% egg production level. Behavioural data were recorded with video cameras during the 4 days. Data were analysed in 6 time periods as 05.00-08.00 am, 09.00-12.00 am, 01.00-04.00 pm, 05.00-08.00 pm, 09.00-12.00 pm and 01.00-04.00 am. Behaviour inspection each hour was divided into 4 quarters and the first 3 min of each quarter were evaluated. Behaviours were represented as the proportion of the total behaviour performed in the time period by a given hen. There was no interaction between hens' behaviour and the genotype at the same egg production level. The frequency of feeding behaviour was found to be significantly lower (P < 0.01), but comfort behaviour was higher (P < 0.05) in hens that were reared in the enriched cages. Only preening was seen as a comfort behaviour due to the cage size. The feeding, drinking, pecking hen, comforting, walking, sitting, resting and perching behaviours changed during the day (P < 0.01). Especially, the transition from light to dark influenced the perching behaviour negatively. No interactions were detected amongst genotype, cage type and time period. Feeding behaviour decreased and the comfort behaviour increased in the hens that were reared in the enriched cages because there were materials that would exhibit different behaviours. Hens in the enriched cage could not suddenly adapt to the dark and light period. For this reason, transitions to light and dark periods in poultry houses should be provided gradually, as in natural life.