This research aimed to determine the meat production indicators and carcass traits of Posavska crested hen, which is the Croatian indigenous chicken breed. The research was carried out on five ...strains of the Posavska crested hen breed: yellow vetch, vetch, red colourful, light gray, and golden brown. Feeding was ad libitum for the whole time, adapted to the age of the chickens from a nutritional point of view. Separation by sex was carried out at the age of four weeks, while slaughter of roosters and determination of carcass traits was done at the age of 18 weeks. The highest average body weight was achieved by roosters of light gray and yellow vetch strain (3542.63 and 3430.38 g, respectively) and light gray pullets (2562 g) at the age of 18 weeks. The lowest feed conversion ratio was achieved by the light gray strain (2.39) at four weeks of age, and by the the roosters of the light gray strain (4.07) and pullets of the light gray and golden brown strain (4.08) at 18 weeks of age. The average dressing percentage was 71.54%, while the highest average dressing percentage was established in the red colourful strain (72.48%). Regarding the proportion of individual parts of the carcass, a significant (P < 0.05) influence of the strain can be seen in the proportion of drumsticks in the carcass, the proportion of which was the highest in the yellow vetch strain (18.69%). A significant influence of the strain was also found regarding L* (P < 0.01) and a* (P < 0.05) skin color indicators. Considering the established differences between the strains, it is necessary to carry out further selection and work on the uniformity of the breed.
The aim of this study was to evaluate the effect of dried
L. leaves as a phytogenic mixture added to broiler feed on CD4
and CD8
T lymphocyte subpopulations, Newcastle disease virus (NDV) antibody ...titres, and the presence of
in faecal samples. The study was conducted on 100 male Ross 308 broilers, divided into four groups of 25 broilers, for a 42-day research period. The groups were housed separately in boxes on a litter of softwood shavings and were fed starter mixture from day 1 to day 21 and finisher mixture from day 22 to day 42. Industrial hemp (
) was grown in the Crkvina area, Croatia (latitude: 45°18'46.8″ N; longitude: 15°31'30″ E). The hemp leaves were manually separated, sun-dried, and ground to a powder. The mixture offered to the control group did not contain cannabis leaves, whereas the three experimental groups received mixtures containing mixed cannabis leaves in a quantity of 10 g/kg, 20 g/kg, or 30 g/kg (E_10, E_20, and E_30, respectively). The mean NDV antibody level was uniform in all study groups until post-vaccination day 14 and increased comparably with time. The percentage of CD4
and CD8
lymphocytes in the peripheral blood subpopulation showed statistically significant differences (
< 0.001) in the E_20 group as compared with the control group and both the E_10 and E_30 groups throughout the study period. As the broiler age increased, the CD4
-to-CD8
ratios also increased and were statistically significant (
< 0.0001) on day 42 in all experimental groups as compared to the control group. Comparing the control group with the experimental groups indicated that the bacterial count was lower in broiler groups having received feed with the addition of 20 g/kg and 30 g/kg
leaves. In conclusion, the
leaves were found to elicit a favourable immunomodulatory effect on cell-mediated and humoral immune responses in broilers via increased CD4
and CD8
lymphocyte subpopulations and higher CD4
:CD8
cell ratios, thus indicating enhanced immune function capacity. In addition,
leaves may have complementary effects on the broiler post-vaccination immune response, increase broilers' resistance to infectious diseases, reduce the effect of stress associated with vaccination, and improve broiler health and welfare.
Current knowledge concerning the possible use and impact of replacing the soybean proteins with those derived from a defatted black soldier fly (Hermetia illucens, HI) meal while feeding chickens to ...produce the meat for human consumption is very limited. This study’s objective was to examine the influence of partial replacement of the HI-defatted flour on chicken meat’s technological properties and quality. 180 one-day-old Ross 308 chicks were divided into three experimental groups (P1, P2, and P3) and one control group counting 45 chicks. The experimental groups were fed with the fattening mixtures containing 15, 25, and 45% of the HI-defatted flour, while the control group was fed in accordance with the standard chicken-fattening requirements. After 42 days, the chickens were slaughtered, and the breasts and drumsticks of 40 chickens were subjected to analysis. A statistically significant difference (P < 0.05) was observed in the P1 for the drip-loss values measured 24 hours after sampling, the muscle resistance to cutting, and the cooking loss values. The water-binding capacity for all three experimental groups did not demonstrate statistically significant differences for the pH1 and pH2 values. Considering the CIE L*a*b* color standard reference values, the results for the breast meat were normally to slightly lighter than normal ones. The basic chemical parameter (water, protein, fat, and collagen) results confirmed that there was no statistically significant difference in any of the experimental groups if compared to the control one.
Commercial high-yielding corn hybrids have not been evaluated for their ability to pigment egg yolk. Therefore, the objective of this research was to investigate the effects of commercial hybrids ...with different carotenoid profiles as the only source of pigments in the diets of hens on yolk color and carotenoid content, as well as the carotenoid deposition efficiency into the yolk. Treatment diets, differing only in one of five corn hybrids, were offered in a completely randomized design in six cages per treatment, each with three hens. Treatment diets and yolks differed in carotenoid profile (contents of lutein, zeaxanthin, β-cryptoxanthin and β-carotene, p < 0.001), with total carotenoid contents ranging from 17.13–13.45 µg/g in diet and 25.99–21.97 µg/g in yolk. The treatments differed (p < 0.001) in yolk color, which was determined by yolk color fan (10.8–9.83) and CIE Lab (redness; range 12.47–10.05). The highest yolk color intensity was achieved by a diet with the highest content of zeaxanthin, β-cryptoxanthin and β-carotene. The deposition efficiency of lutein and zeaxanthin (25.52 and 26.05%, respectively) was higher than that of β-cryptoxanthin and β-carotene (8.30 and 5.65%, respectively), and the deposition efficiency of all carotenoids decreased with increasing dietary content. Commercial corn hybrids provided adequate yolk color and could be the only source of carotenoids in the diets of hens, which could reduce the cost of egg production and increase farmers’ income.
The EZ-DripLoss method is relatively new gravimetric method that is used for the determination of excessive drip in meat. The literature reports diversity regarding the use of EZ-DripLoss ...methodology. In the standardized EZ-DripLoss method, drip loss is calculated as the change in the container weight, whereas in the modified EZ-DripLoss method, it is calculated as the change in sample weight. This technical note aimed to research the relationship between these two methods on chicken breast meat (40 broilers from the line Ross 308) during the measurement interval of 24, 48, and 72 h. The results showed statistically a significant positive linear increase in drip loss values regardless of the used method during all of the investigated measurement intervals. At 24, 48, and 72 h of storage, the average drip loss in the weighed samples was 0.77, 1.40, and 2.23 percentage points greater than in the not weighed samples (
< 0.0001), respectively. A strong and positive estimate of correlation coefficients between the drip loss of weighed and not weighed samples was found after 24 h (r = 0.95), 48 h (r = 0.92), and 72 h (r = 0.86). This technical report indicates that the used EZ-DripLoss methodology highly influences the drip loss in chicken breast meat and the comparisons of the EZ-DripLoss results should be performed with great caution.
Yolk carotenoid profile reflects the hen diet when corn grain is the only source of carotenoids, but corn origin and processing may affect carotenoid utilization. In the present study, 2 commercial ...dent corn hybrids differing in grain hardness (soft- and hard-type) were dried at low (40°C) and high (85°C) temperature and ground through a 5- and 9-mm sieve to investigate their effects on carotenoid bioavailability in laying hens. With 3 hens per cage, 168 Lohmann Brown laying hens were allocated to 8 dietary treatments (2 hybrids × 2 drying temperatures × 2 grinding sieves) in a completely randomized design (8 treatments × 7 cages). The trial lasted 8 wk, during which eggs were collected for analysis every 3 d until carotenoid content stabilized, and then once a week until the end of the experiment. The carotenoid profile of the experimental diets and yolks was analyzed using an HPLC method and deposition efficiency was calculated based on carotenoid contents, yolk weight, egg production and diet intake. The deposition efficiency for lutein, zeaxanthin, α- and β-cryptoxanthin, and β-carotene averaged 27.37, 18.67, 6.29, 3,32, and 0.94%, respectively. As expected, the tested hybrids highly affected the carotenoid content in egg yolk due to their differences in carotenoid profile. Interestingly, hard- and soft-type hybrids differed in the deposition efficiency for all individual carotenoids but not for the total carotenoids. High grain drying temperature tended to increase the bioavailability of lutein and zeaxanthin in both hybrids. For the hard-type hybrid, the content of β-carotene in egg yolk was higher when grains were dried at a high temperature, while the opposite response was found in the soft-type hybrid. The effect of grinding sieve size was important for the zeaxanthin bioavailability in the soft-type hybrid only. In conclusion, our findings showed that corn hybrid had a primary influence on the carotenoid content in the yolks of laying hens, but grain processing may change the bioavailability of carotenoids.
The nutritional value of maize grain can be influenced by its genetic background, which can lead to differences that could affect laying hens due to the high proportion of maize hybrids in the ...complete feed. This study aimed to investigate the effects of modern maize hybrids on hen production and egg quality. Dietary treatments differed only in a grain of 15 high-yielding maize hybrids, added at a fixed proportion of 600 g kg−1 and without additional pigments. By 3 in each cage, 225 Lohmann Brown hens were allocated to 15 dietary treatments in a completely randomized block design (15 treatments × 5 cages). The experiment lasted 10 weeks, during which the number and weight of eggs were recorded daily, and diet intake was recorded weekly. Eggs for quality analysis were collected once per week during the last five weeks of the experiment. Dietary treatments differed (p < 0.05) in complete feed intake (119.7–123.1 g), egg weight (58.02–61.51 g), daily egg mass (56.17–60.16 g), and feed conversion ratio (2.01–2.19). As expected, dietary treatments did not affect egg traits such as shape index, albumen height, Haugh units, shell strength, thickness, and weight, but differed (p < 0.05) in yolk color (6.28–8.76) and yolk (14.74–16.03 g) and albumen (34.39–39.29 g) weights. The findings suggest that using different maize hybrids in complete feeds used in egg production systems may lead to small but significant differences in some hen production and egg quality traits, which in turn affect farmers’ income.
The aim of this study was to evaluate the effect of a supplementation diet for hens consisting of dried basil herb and flowers of calendula and dandelion for color, carotenoid content, iron-induced ...oxidative stability, and sensory properties of egg yolk compared with commercial pigment (control) and marigold flower. The plant parts were supplemented in diets at two levels: 1% and 3%. In response to dietary content, yolks from all diets differed in carotenoid profile (
< 0.001). The 3% supplementation level resulted in a similar total carotenoid content as the control (21.25 vs. 21.79 μg/g), but by 3-fold lower compared to the 3% marigold (66.95 μg/g). The tested plants did not achieve yolk color fan values as the control (13.47) or 3% marigold (11.47), and among them, calendula had the highest values (9.73). Despite the low carotenoid content in diets supplemented with basil herb, iron-induced malondialdehyde (MDA) concentration was low as for marigold (on average 106.83 vs. 92.68 ng/g after 250 min). The treatments differed in sensory color scores for fresh and hard-boiled yolks and flavor while other sensory properties were similar. In conclusion, the supplementation of plants in a hen diet may result in yolks containing carotenoids and other compounds showing a high antioxidant effect.
Transglutaminases (TG) are enzymes that improve the functional properties of proteins in meat products, contribute to the strong cohesion of meat without the further need for the addition of sodium ...chloride or phosphates, and have a positive effect on the texture of the meat product. This study aimed to investigate the physicochemical and sensory attributes of intact and restructured chicken meat supplemented with different TG proportions. The study was conducted on chicken breast meat samples (n = 40) originating from the line Ross 308. The intact samples were separated from the pectoralis major muscle, whereas the rest of the breast meat was ground, divided into equal parts, and supplemented with TG (0.2%; 0.4%; 0.6%; 0.8%; 1%). The intact meat had the highest cooking loss (19.84) when compared to 0.2% (15.51), 0.4% (15.04), 0.6% (14.95), 0.8% (14.95), and 1% (15.79) TG-supplemented meat. The intact meat had greater shear force (16.90) than 0.2% (5.16), 0.4% (5.39), 0.6% (5.16), 0.8% (5.98), and 1% (6.92) TG supplemented meat. There was no difference between intact meat and TG-supplemented meat in color, taste, odor, texture, and overall acceptability (p > 0.05). Therefore, TG supplementation can be used in improving yield and texture of minced chicken meat.
Although the EZ-DripLoss method has been performed in numerous studies, there is a deficiency in our knowledge of the EZ-DripLoss method's suitability for poultry meat analysis. This study aimed to ...research the effect of different sample areas (10, 20, and 30 mm;
= 240), and fiber orientations (vertical vs. horizontal) on the EZ-DripLoss in chicken breast meat measured across a period of five days. The influence of sample area on the EZ-DripLoss of chicken breast meat with respect to the fiber orientation and across the five-day measurement interval was significant between 10 and 30 mm samples, and between 20 and 30 mm samples (
< 0.001). The estimated regression coefficient showed that EZ-DripLoss for the samples with horizontal and vertical fiber direction of 10 and 20 mm, significantly increased by 0.04% per hour, while for the samples with vertical fiber direction whose diameter was 30 mm, it significantly increased by 0.06% per hour, and for the horizontal fiber direction, it significantly increased by 0.07% per hour. The samples with vertical fiber orientation had 0.50% greater EZ-DripLoss compared to the samples with horizontal fiber orientation. EZ-DripLoss evaluation in chicken breast should be performed with a sample core diameter of 20 mm, a vertical fiber orientation, and over the course of longer measurement intervals.
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