Immunostimulatory and Antibacterial Effects of Cannabis sativa L. Leaves on Broilers

The aim of this study was to evaluate the effect of dried Cannabis sativa 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 E. coli 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 (C. sativa) 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 (p < 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 (p < 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 C. sativa leaves. In conclusion, the C. sativa 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, C. sativa 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.

Carotenoid content and deposition efficiency in yolks of laying hens fed with dent corn hybrids differing in grain hardness and processing

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.

Comparison between Standardized and Modified EZ-DripLoss Determination Methods in Chicken Breast Meat

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 (p < 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.

EZ-DripLoss Assessment in Chicken Breast Meat Using Different Sample Areas, Fiber Orientation, and Measurement Intervals

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; n = 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 (p < 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.