The objective of this study was to determine the effect of genotype (slower-growing vs. fast-growing) and production system (access to outdoors vs. indoor) on the growth performance, carcass yield and meat quality (chemical composition, physicochemical and sensory properties) of chickens. The experiment was performed on 1,040 day-old hybrid male chickens of two genotypes. Slower-growing chickens (Hubbard JA957, certified) and fast-growing chickens (Hubbard F15) were fed identical diets until 65 days of age. Both genotypes (each represented by 520 birds) were divided into two subgroups and were raised in pens on litter with outdoor access or in indoor confinement without outdoor access (four replications per subgroup, each of 65 birds). Until day 21, the birds stayed in the indoor facility, in deep-litter pens. The birds could forage on pasture 12 h daily, commencing at three weeks of age. Stocking density was 0.13 m 2 floor space per bird in pens on litter, and 0.8 m 2 per bird in grassy yards. Compared with fast-growing, slower-growing chickens were significantly lighter (by 17%), had a lower breast and thigh muscle yield and a higher abdominal fat content, but they were characterized by higher survival rates at 65 days, a higher protein content and a lower fat content of breast meat. Outdoor access had no negative effects on the growth performance, muscle yield, the fatty acid profile and oxidative status of meat lipids. The meat of free-range chickens was darker in color, it had a higher protein content and a better water-holding capacity, but it was less juicy than the meat of birds raised indoors. (

The objective of this study was to determine the effect of dietary probiotic Pediococcus acidilactici (PA) strain MA18/5M on performance, egg traits, egg cholesterol content, and fatty acid composition in laying hens during a 24-wk period. A total of 222 Hy-Line Brown laying hens, 22 wk of age, were divided into 3 treatment groups. Control group (C) hens were fed a basal diet with no probiotic added. In group PA1, the basal diet was supplemented with PA at 100 mg.kg(-1) of feed for the first 12 wk and 50 mg.kg(-1) feed for the next 12 wk, whereas treatment PA2 was supplemented with 100 mg.kg(-1) feed for the whole trial period. Dietary treatments did not significantly affect the BW, feed intake, and egg production of hens. Pediococcus acidilactici supplementation increased egg weight (P < 0.05), eggshell thickness, eggshell relative weight, and egg specific gravity, and it improved feed efficiency ratio per kilogram of eggs (P < 0.01). Moreover, PA dietary supplementation resulted in a significant (P < 0.05) decrease in the number of broken eggs and eggs without the shell, leading to a significant (P < 0.01) reduction in the number of downgraded eggs (39% for PA1 and 52% for PA2). After 6 mo of probiotic supplementation, significant differences were also found in the fatty acid composition and cholesterol content of egg yolk. The yolk cholesterol content, regardless of PA dose, decreased by more than 10%. The concentrations of total polyunsaturated fatty acids, including linoleic acid and linolenic acid, were significantly higher in treatment PA2 (6.5% increase) than in C and PA1. In conclusion, dietary supplementation of Pediococcus acidilactici MA 18/5M at 100 mg.kg(-1) has potential commercial applications for improvements in hen performance and eggshell quality during the early laying period.

The research hypothesis postulated that the optimal dietary inclusion levels and ratios of lysine ( Lys ), arginine ( Arg ), and methionine ( Met ) can increase the growth potential of hybrid turkeys and limit metabolic disorders that weaken immune function. The experiment was carried out in a full rearing cycle, from 1 to 16 wk of age, in a two-factorial randomized design with 3 levels of Arg and 2 levels of Met (90, 100 and 110% of Arg, and 30 or 45% of Met, relative to the content of dietary Lys), with 6 groups of 8 replicates per group and 18 turkeys per replicate. In the first and second month of rearing, a significant dietary Arg-by-Met interaction was noted for daily feed intake and body weight gain, and a more beneficial effect was exerted by higher Met content and medium Arg content. Throughout the experiment, the higher dietary Met level increased the final body weight (BW) of turkeys ( P = 0.001). Different dietary Arg levels had no influence on the growth performance of turkeys, but the lowest level decreased dressing yield ( P = 0.001), and the highest level increased the percentage of breast muscles in the final BW of turkeys ( P = 0.003). The lowest Arg level (90% of Lys content) undesirably increased the concentration of the proinflammatory cytokine IL-6 ( P = 0.028) and decreased globulin concentration ( P = 0.001) in the blood plasma of turkeys. The higher dietary Met level (45% of Lys content) increased plasma albumin concentration ( P = 0.016). It can be concluded that higher dietary levels of Met (45 vs. 30% of Lys content) and Arg (100 and 110 vs. 90% of Lys content) have a more beneficial effect on the growth performance and immune status of turkeys.

The objective of this study was to determine the physiological effect of supplementing turkey diets with different vegetable oils, i.e. soyabean (S) oil, rapeseed (R) oil and linseed (L) oil, which have different concentrations of polyunsaturated fatty acids (PUFA). The total contents of n-6 PUFA and n-3 PUFA were as follows: diet S, 49.7 and 7.02%, diet R, 33.0 and 7.96%, and diet L, 30.3 and 30.6%; the n-6/n-3 PUFA ratio was 7.3, 4.4 and 1.0, respectively. The experimental materials comprised four groups of turkey hens (14 replications of fifteen birds each). The amount of dietary oil supplementation was increased from 2% in the first four weeks to 6% at the final stage of fattening (14-15 weeks). The apparent total tract digestibility of crude fat in 7-week-old turkeys (2.5% oil in diet) ranged from 89.9 to 91.1%, and showed no statistically significant differences. Dressing percentage, breast, thigh, and drumstick muscle contents did not differ among groups. Group L had a significantly higher intestinal fat weight (0.84% body weight (BW)) than the other groups (0.60-0.62%). In comparison with diet S, diets R and L contributed to a significant decrease in the levels of saturated fatty acids (from 32.9% to 30.3 and 30.2%) in breast meat lipids. In group L turkeys, the share of PUFA in total fatty acids in breast meat lipids was significantly higher (37.3% .1% in groups S and R, respectively), and the n-6/n-3 PUFA ratio was significantly lower (1.2 vs 5.6 and 5.1). As for the performance indices (final BW, feed conversion ratio), both rapeseed and linseed oils could be recognized as comparable alternatives to soyabeen oil (in both cases P>0.05 vs S group). However, the highest final BW followed the dietary treatment with linseed oil (P<0.05 vs group R).

This study was conducted to determine the effect of probiotic Pediococcus acidilactici ( PA ) strain MA18/5M supplementation of diets with different dietary energy levels on productive performance, egg quality, and body composition in Hy-Line Brown hens during a 16-week period from 32 to 47 wk of age. The experimental treatments with a 2 × 2 factorial design received a 2 wheat–corn–soybean diet: a moderately low energy density diet with 2,650 kcal ME/kg ( M-LED ) and a low energy density diet based on the M-LED diet with 2,550 kcal ME/kg ( LED ), each diet without and with probiotic supplementation (M-LED, LED, M-LEDp , and LEDp , respectively). Reduced dietary energy levels had a particularly negative effect on egg weight (61.7 vs. 63.3 g; −2.6%, P < 0.001), egg mass output (1.67 vs. 1.71 kg; −2.4%, P = 0.015), and FCR (2.01 vs. 1.97 kg feed/kg egg; +2%, P = 0.028). In hens administered the LED diet, deteriorated productive performance was accompanied by greater body weight loss ( P < 0.001) and reduced abdominal fat content ( P < 0.033) as compared with the M-LED group. Dietary probiotic inclusion increased egg weight ( P = 0.015), including relative eggshell weight ( P = 0.008) and eggshell thickness ( P = 0.002) and significantly improved FCR ( P = 0.010). No interactions between the PA-based probiotic and dietary energy levels were found in any of the tested parameters. Adding the probiotic on top of the M-LED diet improved layers performance but resulted in nonbioequivalence for the egg weight, egg mass output, and FCR compared with this group without probiotic. Probiotic supplementation of the LEDp diet improved all performance parameters except for egg weight. As a result, the laying rate, egg mass output, daily feed intake, and FCR in the LEDp treatment were bioequivalent to those noted in the M-LED group without the probiotic. The results of a bioequivalence test suggest that a low energy diet fed to laying hens promoted a probiotic response to improve energy utilization by birds.