Tannins are a diverse group of plant phenolic compounds. Condensed tannins (CTs) represent a major subgroup of tannins and were extracted from tilia (Tilia L.) flowers and black locust (Robinia pseudoacacia) leaves. These extracts were examined for their effects on the metabolic profile of chicken caeca. By using in vitro, a nuclear magnetic resonance (1H-NMR), which was combined with multivariate statistics, the current study was applied for the first time to investigate how three different CT compositions, procyanidins (PC) and/or prodelphinidins (PD) units influenced the metabolic end-products in caecal contents of chickens. In the presence of tannins, glutamate, leucine, lysine, pyroglutamate, phenylalanine, proline, and sarcosine were significantly decreased. CT extracts significantly influenced the fermentation, increasing the concentrations of some fatty acids such as acetate, butyrate, and propionate whereas. In contrast, lactate decreased between the treatments. This study identified the key structural features of CTs that contain either high molar proportions of PD or PC, which might be useful to improve the efficiency of feed utilization in chickens.

Introduction: Thyroid hormones affect protein turnover, and in the case of hypothyroidism a decrease in protein synthesis and reduced release of certain amino acids from skeletal muscles are observed. Changes in the amino acid system of skeletal muscles may be responsible for the occurrence of muscle disorders. Material and Methods: The study measured the content of selected amino acids in the gastrocnemius muscle of Wistar rats during experimental hypothyroidism induced by oral administration of methimazole at a concentration of 0.05% in drinking water for 90 d. The rats were divided into four groups: E1 (n = 6) - experimental males, E2 (n = 6) - experimental females, C1 (n = 6) - control males, and C2 (n = 6) control females. Results: A statistically significant reduction occurred in leucine, isoleucine, and 1-methylhistidine levels in males, and 1-methylhistidine in females, in comparison to the control groups. Conclusion: The hypothyroidism-induced changes in amino acid content may be responsible for the occurrence of skeletal muscle function disorders.

There is scarce information on the effects of feed storage period on poultry performance, which has not been investigated thus far. The aim of this study was to evaluate the effect of feeding broilers on feeds stored for different periods, with or without supplemental amino acids and vitamins. This study followed a factorial design (3 x 3), i.e. three dietary treatments and three feed storage periods. The three dietary treatments consisted of 1) a basal diet, 2) a basal diet including additional 5g methionine and 13 g lysine/kg, and 3) a basal diet including 3 g vitamin premix/kg. The 3 dietary treatments were tested with feeds stored for three different periods (Fresh, 4-months, and 6-months). A total of 450 one-day old broiler chicks were randomly assigned to the 9 treatments, each treatment contained 5 replicates of 10 chicks each (n = 50/group). The experiment lasted for 42 days. The results indicated that the final BWs of the birds received 4- or 6-months stored feed were greater than that of those fed fresh diets. The best total BWG was seen in the 4-month-stored feed group. There was no significant effect of storage period on total FC and FCR during period from 0 to 6 weeks of age, but the FCR tended to be better with the feed stored for 4 months. Haemoglobin was significantly higher in the birds fed fresh or 4-month stored feed. The percent of liver and spleen of the birds received 6-month-stored feed were the highest (P ˂ 0.01). Plasma content of albumin was higher in the birds received 4-or 6-month stored feed than the fresh diet. The use of additional amino acids increased the final BW and total BWG than those of the control and vitamin-supplemented treatments. The main effect of dietary treatments on percentages of immune organ weight was insignificant. The control (basal diet) recorded higher lymphocytes percentage, while T2 (BD + double level of amino acids) recorded higher eosinophil, heterophil and H/L ratio, whereas T3 (BD + double level of vitamins) recorded higher levels of haemoglobin, eosinophil, and monocytes. The main effect of dietary treatments on blood plasma proteins was insignificant. The tested treatments did not show a significant effect on broilers mortality. The detected values of AF1, AF2, AG1, and AG2 were very low in all 9 diets. In conclusion, enrichment of broiler feeds with higher levels of lysine and methionine (double level of NRC, 1994) together with antioxidants supplement could prolong their shelf-life to 6 months without any deleterious impact on productive performance of broiler chickens.