Effects of Persimmon Peel on Laying Performance,Nitrogen Availability,and Egg Quality in Laying Hens Provided with Shrimp Meal Diets

To determine whether persimmon peel (PP) showing high chitinase activity could alleviate the detrimental dietary effects of chitin-rich shrimp meal (SM), we assessed the laying performance, nitrogen (N) balance, and egg quality of laying hens provided with SM diets containing PP. We also examined the color and antioxidant properties of egg yolk, as we anticipated these would be improved by providing SM and PP. Seventy-two laying hens (45 weeks of age) were allotted to one of the nine dietary treatments (eight hens each), namely three levels of SM (0%, 10%, and 15%)×three levels of PP (0%, 6%, and 8%), and fed with the experimental diets over a period of 6 weeks. Hen-day egg production, feed intake, egg mass, feed conversion ratio, and N balance reduced with increasing levels of SM, whereas the reductions were recovered in a dose-dependent manner in response to increasing levels of PP; however, the SM0% treatment showed that PP exerted little effects. Notably, reductions in the Haugh unit and albumen height of eggs with increasing SM levels, and recovery by provision of increasing levels of dietary PP, were observed. Yolk color was improved by SM, although PP exerted little effect, whereas the antioxidant properties of yolk were enhanced by the inclusion of both SM and PP in diets. Furthermore, eggshell strength, weight, and thickness were enhanced with increasing levels of SM, whereas dietary PP had little effect on these parameters. Thus, we suggest that PP can alleviate the negative effects of dietary SM and improve egg quality, without causing a reduction in laying performance, provided that the level of supplementary PP in diets is less than 8%. These findings accordingly indicate that PP is a promising feed constituent for laying hens fed with SM diets.     

Improvement in the in vitro Digestibility of Shrimp Meal by the Addition of Persimmon Peel

The present study was conducted to analyze the chemical properties of persimmon peel (PP) and the in vitro digestibility of shrimp meal (SM) diets containing PP. Discussions whether PP can be used as a feed additive to promote digestion of SM in chickens are also included. The chemical composition and chitinase activity of dried PP was studied. SM diets containing PP were formulated according to the 4 by 6 factorial design: 4 levels of SM (0%, 10%, 15%, and 20%) × 6 levels of PP (0%, 2%, 4%, 6%, 8%, and 10%). The in vitro digestibility of dry matter (IVDMD), crude protein (IVCPD), and chitin (IVCD) was also studied. PP was rich in nitrogen-free extract (NFE, about 74%) and tannin (2.8%), and the highest chitinase activity of PP was observed at pH 4.5. Approximately 50% of chitinase activity was also observed at acidic (3.0) and alkaline (8.0) pH. Its activity was slightly affected by pepsin treatment. IVDMD increased upon addition of up to 8% PP, but decreased with an increase in the level of SM. When PP level was increased up to 6%, IVCPD in the group containing 0% SM, changed slightly; however, an increasing trend was observed in the other groups. When PP level was more than 6%, IVCPD decreased in all the groups. IVCD increased dose-dependently with increasing level of PP and decreased with increasing level of SM. In conclusion, PP was rich in NFE, had high chitinase activity, and improved all digestibility parameters, such as IVDMD, IVCPD, and IVCD, in SM diets where the PP level was under 6%. Thus, up to 6% of PP can be safely included in SM diets as a digestion promoter.