Comparative evaluation of nutrient composition, in vitro nutritional value, and antioxidant activity of de-oiled meals from walnut, hazelnut, almond, and sesame.

This study aimed to establish a comparative database on the chemical composition, in vitro nutritional value, and antioxidant activity of the de-oiled meals produced from walnut, hazelnut, almond, and sesame seeds from the ruminant nutrition perspective. The meals were provided in dried form after their oil harvest using the cold-pressing oil extraction method. Crude protein (CP) constituted the major component of the meals and was the greatest in walnut and almond (average of 45.6% of dry matter (DM)], intermediate in hazelnut meal (41.4%), and least in sesame meal (33.3%)). Potassium was the most abundant mineral in walnut, hazelnut, and almond meals, followed by phosphorus, calcium, and magnesium. The CP fractions determined using the Cornell Net Carbohydrate and Protein System were largely different across the meals, with fraction A being the greatest in hazelnut (40.9% of CP) and intermediate in almond, sesame, and walnut meals (11.4% of CP). The unavailable CP fraction (fraction C) was the least abundant fraction in all meals, ranging from 0.13% of CP in walnut to 3.30% of CP in hazelnut meal. Oleic and linoleic acids were the predominant unsaturated fatty acids, and palmitic acid was the principal fatty acid in all meals analyzed. The fractional degradation rate (h-1) ranged from 0.043 in almond meal to 0.017 in walnut meal. In vitro intestinal CP digestibility (% of rumen-undegraded protein) ranged from 91.6 in hazelnut meal to 97.2 in almond meal. Total phenolics expressed as milligram tannic acid equivalent/gram DM was greatest in walnut meal (11.9), resulting in the greatest antioxidant activity recorded for walnut meal (83.2%). This study provided a database on the nutrient composition, in vitro nutritional value, and antioxidant capacity of the selected de-oiled meals. Additional investigation is needed to identify the in vivo response of their inclusion in the diet of ruminants.

Efficiency of plant-based acaricide gels compared to fluvalinate-impregnated strips for control of Varroa destructor in honey bee colonies.

The Varroa mite is one of the most important pests of honey bee colonies. This study compares the efficiency of thymol-based acaricides with the tau-fluvalinate-based commercial treatment to control this mite species. Two experiments were conducted: (1) in the Fall, thymol-based gel was compared with a widely used acaricide, fluvalinate-impregnated strips (Apistan®), and (2) in the Spring, gels containing thymol-only, thymol + menthol + eucalyptus essential oil, and thymol + thyme essential oil were compared with fluvalinate-impregnated strips. In the first experiment, both treatments reduced Varroa mite infestation levels significantly after 70 days of their application compared to the control treatment. The results of the second experiment showed that thymol + thyme essential oil gel, thymol + menthol + eucalyptus essential oil gel, and Apistan strips had always higher efficiency on decreasing mite infestation levels of the selected colonies compared to the control treatment and thymol-only gel during their 7-week application. The results of this study demonstrate that plant-based acaricides for controlling Varroa mites in honey bee colonies have similar efficiency compared to the chemical control methods. Therefore, it is better to use these selected acaricides to reduce mite resistance to chemical control treatments in honey bee colonies.