The present study was conducted to investigate the effects of dietary supplementation with vitamin E, vitamin C, and Se, alone or in combination, on carcass characteristics, oxidative stability and meat quality parameters of breast meat from broilers exposed to cyclic heat stress (HS), and stored under different conditions. A total of 120 one-day-old male Ross 308 broilers were randomly assigned to six dietary treatments: NRC (minimal nutrition requirements), AVI (commercial nutritional recommendations for Ross 308 broilers), AVI + vitE (as AVI + 200 IU vitamin E/kg feed), AVI + vitC (as AVI + 250 mg vitamin C/kg feed), AVI + Se (as AVI + 0.2 mg Se/kg feed), and AVI + ECSe (as AVI + vitE + vitC + Se). From day 26 onwards, all birds were exposed to a high ambient temperature (31 °C) for 8 h per day. The results showed that dietary vitamin E alone or in combination with vitamin C and Se significantly increased the α-tocopherol content and decreased the malondialdehyde (MDA) content in breast meat. Although no obvious synergistic effects of the added antioxidants were observed, the addition of higher levels of vitamin E, vitamin C and Se to broiler diets had no adverse effects on carcass traits, oxidative stability and meat quality parameters when supplemented either alone or in combination.

The aim of the current study was to assess the antioxidative effects of the dietary supplementation of olive leaf extract (OLE) in different concentrations compared to those of vitamin E in piglets under conditions of dietary n-3 PUFA-induced oxidative stress. Forty-eight castrated male piglets (10.6 ± 0.99 kg) were fed the following experimental diets: Cont− (low-fat diet, no supplement), Cont+ (high linseed oil diet, no supplement), Vit-E (as Cont+, 105 IU vitamin E/day), OLE-1 (as Cont+, 3.84 mg hydroxytyrosol equivalents (HEQs)/day), OLE-2 (as Cont+, 38.4 mg HEQ/day), and OLE-3 (as Cont+, 96 mg HEQ/day). After 21 days of feeding, the experimental diets, blood and urine samples were collected to assess the extent of the oxidative stress. Results indicated that diet OLE-1 lowered the activity of gamma-glutamyl transferase, protected DNA (measured as DNA tail %) and altered urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG). Dietary vitamin E lowered the levels of urinary F₂-isoprostanes, as well as of plasma malondialdehyde and γ-tocopherol, but raised the plasmatic α-tocopherol and altered the level of urinary 8-OHdG. In conclusion, only minor positive effects of dietary OLE on the oxidative stress parameters were observed. Additionally, OLE did not show concentration dependence.

Over the last decade, the two-phase centrifugation system for olive-oil extraction has become dominant in Slovenia. There are many suggestions for the exploitation of two-phase OMW, but among the suggested methods, direct spreading on agricultural land appears to be operationally simple and economically feasible for Slovenia. As there is little information available about two-phase OMW produced in the northern Mediterranean regions, the aim was to determine its composition and evaluate its use as a soil amendment in olive groves. This study shows that the characteristics of two-phase olive-mill waste produced in northern Mediterranean regions are similar to those of other countries. In addition, the calcareous characteristics of the Mediterranean soil can reduce its phytotoxic effects and might thus represent a natural system for olive-mill waste treatment. Phenolic compounds in the two-phase olive-mill waste are rapidly decomposed, and the soil has a high buffering capacity. Furthermore, the results of the soil analysis also showed some effects on the soil properties, such as a significant increase in K₂O and soil organic carbon. The combined application of two-phase olive-mill waste and mineral fertilizer to olive groves on eutric cambisols has positive effects on the physical, chemical and biochemical properties of the soil.

This study investigated the individual and combined effects of a high dietary n-3 PUFA intake and cyclic heat stress (HS) on the carcass characteristics, meat quality, and oxidative stability of broiler breast meat and the potential of antioxidant supplementation (vitamins E, C, and selenium) to mitigate these effects. A total of 192 one-day-old male Ross 308 broilers were randomly assigned to 24 pens within two controlled environment chambers and fed with the following diets: a basal diet low in antioxidants according to NRC recommendations (NRC group), a basal diet according to Aviagen recommendations additionally supplemented with 200 IU/kg vitamin E, 250 mg/kg vitamin C, and 0.15 mg/kg selenium (HAOX group), and these two diets further supplemented with 5% linseed oil (NRC N-3 and HAOX N-3 groups). On day 22, the broilers were exposed to the following two environmental conditions: thermoneutral (TN, 21 °C) or cyclic HS (HS, 34 ± 1 °C, 7 h/d) in a 2 × 2 × 2 factorial design. A high intake of n-3 PUFAs significantly decreased growth performance, dressing percentage, and breast yield, while the incidence of pale, soft, and exudative (PSE) meat characteristics and malondialdehyde (MDA) levels increased. Cyclic HS reduced body weight (BW) and average daily feed intake (ADFI), but had limited effects on meat quality. No interactions between n-3 PUFAs and HS were observed for any measurements. High antioxidant supplementation increased breast yield, improved meat quality, and reduced oxidative stress, as evidenced by an enhanced antioxidant activity and lower MDA levels. In conclusion, n-3 PUFAs had a negative effect on both the carcass characteristics and meat quality of broilers, while HS primarily affected only carcass characteristics, with neither stressor having severe adverse effects. High levels of antioxidants could mitigate the negative effects of dietary- and heat-induced oxidative stress by enhancing the oxidative stability of broiler meat.

The gastrointestinal tract of broilers is susceptible to oxidative stress induced by heat stress (HS) and diet, which can be mitigated by the supply of exogenous vitamins and antioxidants. The aim of this study was to compare the extent of the effects of cyclic HS, and high levels of polyunsaturated fatty acids (PUFA) (HP) on gut health. It also aimed to investigate whether additional supplementation with vitamins E, C and selenium (HA) is required to support gut health under these conditions. In the present study, 192 one-day-old male Ross 308 broilers were randomly divided into eight experimental groups. Exposure to HS and HP significantly (p < 0.001) decreased villus height and villus-to-crypt ratio in the duodenum, while no differences were observed in the jejunum and ileum. In addition, oxidative stress in the liver, indicated by increased malondialdehyde (MDA) levels, was increased in the HP groups (p < 0.0001), while the HA groups had a positive effect on lowering MDA levels. The results confirm that cyclic HS and HP induce oxidative stress that damages the structure of intestinal morphology and that supplementation with HA could be a potential approach to mitigate the negative effects of these stressors.

Introduction As in other animals, oxidative stress in broilers most often occurs as a consequence of nutrition, high environmental temperatures, or other pathological conditions such as increased activity of the immune system (e.g., infection,