Panagiotis E. Simitzis

Effect of dietary oregano oil supplementation on lamb meat characteristics.

The effect of dietary oregano essential oil supplementation on lamb meat characteristics was investigated. Eight male and eight female Chios lambs were divided into two equal groups. The first group was fed with the control diet consisting of concentrated feed and alfalfa hay, whereas the second group consumed the same diet, the only difference being that the concentrated feed was uniformly sprayed with oregano essential oil (1ml/kg). Duration of the experimental period was two months. No differences were observed after oregano essential oil supplementation in final body weight (kg), body weight gain (g) and carcass yield (%). Tenderness of longissimus thoracis muscle, expressed as sarcomere length and shear force value, was not influenced by the treatment, whereas pH and colour parameters (yellowness-redness) appeared to increase (P<0.05). Moreover, results showed that dietary incorporation of oregano essential oil exerted strong antioxidant effects retarding lipid oxidation (MDA formation) in meat during refrigerated and long-term frozen storage (P<0.001).

Feeding preferences in lambs influenced by prenatal flavour exposure

The aim of the present study is to highlight and evaluate the role of flavour prenatal exposure in postnatal feeding preferences in sheep after weaning and until the early stages of puberty. 16 lambs were selected from two groups of ewes; the first group was fed with a control diet, consisted of concentrated feed and alfalfa hay and the second group with the same diet, with the only difference that the concentrate was supplemented with oregano essential oil (1 ml/kg), during the period of pregnancy (50th-130th day). Lambs were later individually subjected to feeding preference tests, at the age of 3, 4.5, 6, 7.5 months old. Each test lasted 25 min and it was a free choice situation between 3 different test feeds supplemented with eucalyptus or orange or oregano essential oil (1 ml/kg). Lambs born to oregano-treated ewes ate higher amounts of the oregano supplemented test feed during all feeding preference tests compared to lambs from the control group (P<0.01). Rates for occurrences and duration of eating were also greater in lambs born to oregano-treated ewes than the offspring of the control ewe group (P<0.01). On the other hand, animals without a flavour exposure precedent did not exhibit an evident strong preference for a specific test feed, although orange supplemented feed tended to be more preferable compared to the other offered feeds. Average total intake of lambs were not different between groups during all feeding preference tests at 3, 41/2, 6 and 71/2 months old. As it is concluded, prenatal exposure to oregano essential oil via maternal ingestion drastically influences lamb feeding preferences till adulthood.

The effects of dietary oregano oil supplementation on pig meat characteristics

The effects of different concentrations of dietary oregano essential oil supplementation on finishing pig meat characteristics were investigated in the present study. Thirty-two barrows and thirty-two gilts were divided into four equal groups. During the experimental period, which started when the animals were 5 months old and finished after 35 days, the first group was fed the control diet (group C), whereas the other three groups consumed the same diet, with the only difference that the feed was supplemented with oregano essential oil at concentrations of 0.25, 0.5 and 1 ml/kg of fed diet (groups OR1, OR2 and OR3, respectively). At the end of the experiment, pigs were fasted for 12 h, weighed and slaughtered. After overnight chilling, a 50 cm loin section was removed from the half of the carcasses (8 pigs per nutritional treatment; 4 barrows and 4 gilts) and transported to laboratory for further examination. No significant differences were observed after dietary oregano essential oil supplementation in final body weight (kg), body weight gain (g) and dressing out (%). Tenderness of longissimus muscle, expressed as shear force value, pH values at 45 min and 24 h postmortem, colour parameters and sensory attributes of eating quality were not significantly influenced by the dietary treatment. Moreover, the lipid oxidation results suggested a lack of antioxidant effect for the oregano essential oil. In conclusion, carcass and meat quality attributes were unchanged, indicating that the dietary administration of different levels of oregano essential oil did not exert any effect on pig meat parameters in the present experiment.

The effects of quercetin dietary supplementation on broiler growth performance, meat quality, and oxidative stability

The present study was conducted to describe the effects of quercetin dietary supplementation, at levels of 0.5 and 1 g/kg of feed, on growth performance, internal organ weights, meat quality, and meat oxidative stability during storage of broiler chickens reared from hatching to 42 d of age. Body weight and cumulative feed intake were not affected by quercetin supplementation (P > 0.05). However, poorer feed conversion ratio values were obtained with increasing levels of dietary quercetin (P-linear < 0.05). Relative heart weight was significantly higher for chickens that were given quercetin in comparison with the controls (P < 0.05). The rest of the internal organ weights measured (liver, spleen, and fat pad) and meat quality traits were not affected by dietary supplementation with quercetin, except for meat lightness and redness. Meat oxidative stability, expressed as nanograms of malondialdehyde per gram of meat, was improved (P < 0.05) during refrigerated storage for 3 and 9 d, when birds were fed quercetin at a level of 1 g/kg of feed. It is concluded that the incorporation of quercetin in broiler diets could prolong meat shelf life by reducing the rate of lipid oxidation, and increase relative heart weight, potentially contributing to improved animal health.

Impact of stocking density on broiler growth performance, meat characteristics, behavioural components and indicators of physiological and oxidative stress.

1. The study was designed to assess the impact of stocking density (6 and 13 birds/m2 equivalent to 12·6 or 27·2 kg/m2, respectively) on growth performance, meat quality, behaviour, and indicators of physiological and oxidative stress as measures of bird welfare. 2. The higher stocking density negatively affected final body weight and feed intake but not cumulative feed conversion rate. Muscle colour traits, pH24, cooking loss and shear values were not affected. Birds reared at the lower density showed higher intramuscular fat, liver weight, liver NADP-isocitrate and NADP-malate dehydrogenase activity. 3. Higher stocking density was associated with decreased locomotor activity and increased physiological (H:L ratio and bursa weight) and oxidative (glutathione concentrations and reduced:oxidised glutathione ratios) stress indicators. 4. The results show that stocking density did not significantly affect broiler meat quality characteristics but higher density decreased growth performance, increased physiological and oxidative stress levels and decreased locomotor activity.

Effect of hesperidin dietary supplementation on hen performance, egg quality and yolk oxidative stability

Abstract 1. The purpose of this study was to evaluate the effects of dietary supplementation with hesperidin (one or 3 g/kg of feed) for 31 d on the performance, egg quality and yolk oxidative stability of brown and white laying hens (26-wk old). 2. Supplementation with hesperidin did not affect egg production, egg weight and egg quality traits. 3. No hesperidin effect on yolk and plasma cholesterol was observed. A strain effect was found with lower total and per g yolk cholesterol of brown hens in comparison to the white ones. 4. Oxidative stability of egg yolk, expressed as ng MDA/g yolk, was significantly improved in the hesperidin groups even from the first week of supplementation. At the same time, a significant improvement in the oxidative stability of egg yolk due to the incorporation of hesperidin in hens’ diet was observed after 30 and 90 d of storage at 20°C and 4°C, respectively. 5. No hesperidin by strain interaction was detected for any of the traits measured. 6. In conclusion, incorporation of hesperidin to laying hens’ feed did not affect productive and egg qualitative traits. On the other hand, dietary hesperidin supplementation significantly improved oxidative stability of both fresh and stored eggs. Antioxidant properties of hesperidin seem to make it a promising natural agent for improving the shelf life of eggs.

The Influence of Naringin or Hesperidin Dietary Supplementation on Broiler Meat Quality and Oxidative Stability.

An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin or naringin, on growth performance, carcass characteristics, breast meat quality and the oxidative stability of breast and thigh meat. Two hundred and forty 1-day-old Ross 308 broiler chickens were randomly assigned to 6 groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other five groups were given the same diets further supplemented with naringin at 0.75 g/kg (N1), naringin at 1.5 g/kg (N2), hesperidin at 0.75 g/kg (E1), hesperidin at 1.5 g/kg (E2) and a-tocopheryl acetate at 0.2 g/kg (E). At 42 days of age, 10 chickens per treatment group were slaughtered for meat quality and oxidative stability assessment. No significant differences were observed among groups in final body weight, carcass weight and internal organs weights (P>0.05) apart from liver that decreased linearly with increased levels of naringin (P-linear<0.05). Regarding the breast meat quality parameters, only redness (a*) value was higher in E1 and N1 group compared to VE group (P<0.05), while all the others i.e. shear values (N/mm2), pH24, cooking loss (%) and L* and b* color parameters were not significantly different among groups (P>0.05). Measurement of lipid oxidation values showed that after hesperidin and naringin dietary supplementation, malondialdehyde values decreased in tissue samples in a dose depended manner (P-linear<0.05). In conclusion, hesperidin and naringin, positively influence meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing as important additives for both the consumer and the industry.

The effects of dietary cinnamon (Cinnamomum zeylanicum) oil supplementation on broiler feeding behaviour, growth performance, carcass traits and meat quality characteristics

Abstract The aim of this study was to investigate the effects of dietary supplementation with cinnamon oil on growth performance, behaviour, carcass traits and meat quality of broilers. One hundred and thirty-five Cobb 700 day-old broiler chickens were randomly assigned into three equal treatment groups with three replicates (pens) of fifteen chickens each. The dietary treatments consisted of the basal diet as control (C) and basal diet supplemented with 0.5 (C1) or 1.0 (C2) ml of cinnamon oil per kg of feed. On day 49, 5 birds from each pen (15 per treatment) were slaughtered and the pectoralis major muscle samples were collected for meat quality evaluation. No effect of cinnamon oil supplementation on the probability of a bird standing at the feeder or the drinker was observed until the age of 17 days. Moreover, cinnamon oil supplementation did not affect body weight, feed intake and feed conversion ratio. No significant differences were also found in internal organs’ weights and carcass characteristics among the treatments, although cold carcass weight was the lightest in the C1 group. At the same time, colour parameters, pH24, cooking loss, intramuscular fat and shear values were not affected by diets. The extent of lipid oxidation in raw pectoralis major muscle stored at 4ºC for up to 9 days or at -20ºC for up to 6 months was also not influenced by the dietary treatment. The present findings suggest that cinnamon oil at the selected concentrations may not have the potential to improve broiler growth performance, carcass and meat quality characteristics.

Effect of dietary protein source on piglet meat quality characteristics

An experiment was conducted to examine the effects of different dietary protein sources (soybean meal vs whey protein) on piglet meat quality characteristics. Eighteen castrated male Large White × Duroc × Landrace piglets were randomly assigned to 2 groups. Piglets were kept in individual metabolic cages and fed ad libitum over a period of 38 days the following 2 diets: diet SB, which was formulated to meet the nutrient requirements of piglets using soybean meal as the main crude protein source and diet WP, where SB was totally replaced by a mixture of whey proteins on equal digestible energy and crude protein basis. At the end of the experiment, piglets were weighed and slaughtered. After overnight chilling, samples of Longissimus dorsi muscle were taken and were used for meat quality measurements. No significant differences were observed in the values of pH, color, water holding capacity, shear force and intramuscular fat content of L. dorsi muscle between the dietary treatments. Measurement of lipid oxidation values showed that dietary supplementation with different protein sources did not influence meat antioxidant properties during refrigerated storage. The SB piglets had lower C14:0 (P<0.01) and higher C18:3n-3 (P<0.001) levels in intramuscular fat in comparison with WP piglets. However, these changes were attributed to background differences in the dietary FA profile and not to a direct protein source effect. The results of this preliminary study indicate that the examined dietary protein sources do not have a significant effect on meat quality characteristics of piglets.

Effect of cinnamon (Cinnamomum zeylanicum) essential oil supplementation on lamb growth performance and meat quality characteristics.

A trial was conducted to examine the effect of cinnamon essential oil supplementation on lamb growth performance and meat quality. Sixteen male lambs were randomly assigned to two groups. The first group served as control and was given a basal diet, and the second group was given the same diet supplemented with cinnamon oil (1 ml/kg of concentrated feed) for 35 days. Incorporation of cinnamon oil did not affect growth performance (P>0.05). Meat pH, colour, water-holding capacity, shear force, intramuscular fat and lipid oxidation values of longissimus thoracis muscle were not significantly influenced by cinnamon oil supplementation (P>0.05). The post-inoculation counts of Salmonella enteritidis and Listeria monocytogenes on raw meat during refrigerated storage for 6 days did not differ (P>0.05) between the two groups. The results show that cinnamon oil supplementation may not have the potential to improve lamb growth performance and meat quality characteristics.