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Summary Common pathogens of intensive poultry farms, either parasitic or bacterial, such as Coccidia or Salmonella, are well known and strictly controlled by veterinary management. This case study reports an unusual case of runting stunting syndrome (RSS) observed on a Sicilian poultry farm of broiler chickens during 2019. The investigation was carried out on five chickens which present delayed in body weight and growth performance. Animals showed also difficulty in deambulation and diarrhea. At necropsy, intestinal lesions were detected in three of the five clinical cases. Gut samples were collected and analyzed to identify potential pathogens responsible for the RSS. Presence of viruses was detected by using quantitative reverse transcription PCR (RT‑qPCR), while selected tissues were fixed and embedded in paraffin wax according to routine procedures. All histological sections were stained with hematoxylin‑eosin. RT‑qPCR successfully detected both Chicken astrovirus (CAstV) and Avian orthoreovirus (ARV). Histology evidenced severe specific lesions on the intestinal mucosa in liver and kidneys. Chicken astrovirus and Avian orthoreovirus RNA was also detected in cecal tonsils, kidney and liver, thus implying their possible primary role in inducing the disease. Further studies are needed to evaluate the role of other possible factors (low biosecurity measures, e.g.) and, most of all, the consequences in terms of economic losses and animal health impairment.

In the present study, we have hypothesized that replacing barley with high proportions of dried citrus pulp in a concentrate-based diet for lambs could increase the intake of unsaturated fatty acids and could reduce the rate of the ruminal biohydrogenation of PUFA, with a consequent improvement of the intramuscular fatty acid composition. To test this hypothesis, 26 Comisana lambs were divided into 3 groups and for 56 d were fed a barley-based concentrate diet (CON; 8 lambs) or 2 diets in which barley was replaced with 24% (CIT24; 9 lambs) or 35% (CIT35; 9 lambs) dried citrus pulp. An overall improvement of the fatty acid composition of LM from lambs fed citrus pulp-containing diets was found. The PUFA/SFA ratio was lower (P < 0.05) in the LM from lambs in the CON group compared with both the CIT24 and CIT35 groups. The thrombogenic index was lower (P < 0.05) in meat from lambs fed the CIT35 diet compared with those fed the CON diet. The CIT35 diet increased the proportion of C20:5 n-3 in the LM (P < 0.05), whereas the CIT24 diet enhanced that of C22:6 n-3 (P < 0.05) compared with the CON diet. Some of these results might be explained considering that feeding the CIT24 and CIT35 diets increased the intake of total fatty acids (P < 0.05) and of C18:3 n-3 (P < 0.01) compared with feeding the CON treatment. On the other hand, phenolic compounds present in citrus pulp could have inhibited the ruminal biohydrogenation of PUFA. This is supported by the fact that regardless of the level of inclusion in the diet, citrus pulp increased the proportion of rumenic acid (P < 0.001) in LM compared with the CON diet. The plasma from lambs fed both CIT24 and CIT35 diets had a greater percentage of vaccenic acid (VA; P < 0.001) compared with that from lambs fed the CON diet, and the CIT35 diet increased the proportion of rumenic acid in plasma compared with the CON treatment (P < 0.05). In the ruminal fluid, stearic acid (SA) tended to decrease, and the sum of CLA tended to increase (P = 0.09) with increasing level of citrus pulp in the diets. Furthermore, the SA/(SA + VA) ratio tended to be lower (P = 0.10) in the ruminal fluid from lambs fed the CIT35 diet compared with that of the CON group. In conclusion, our results support the hypothesis that replacing barley with citrus pulp in the diet of growing lambs improves intramuscular fatty acid composition and underline the need for specific studies to clarify the mechanisms by which feeding citrus pulp affects the fatty acid metabolism in ruminants.