The effects of different levels of dried citrus sinensis peel on broiler carcass quality

Background: The peel of citrus is a by-product of the juice production industry and is a source of natural antioxidants. The need for natural antioxidants in food, cosmetics and pharmaceuticals has resulted in extensive scientific research in this field in recent decades. Seeds and peels of some fruits have more antioxidant activity than their flesh. The most important source of vitamin C is citrus fruits. Vitamin C is an antioxidant against free radicals and prevents cell damage. Orange peel ingredient contains vitamin C, phenolic compounds, ascorbic acid, pectin, coumarin, volatile oils, flavonoids and flavones, including hesperidin, naringenin, nobiletin, D-limonene and pigments (carotenoids). It is expected that the use of Citrus sinensis by products in broiler diets will improve carcass quality of broilers. The experiment was conducted to evaluate the effects of different levels of dried Citrus sinensis peel (DCSP) on carcass quality of broilers. Materials, Methods & Results: Four hundred Ross 308 day-old broilers were used in a completely randomized design with five treatments. Each treatment had four replicates, and each replicate had 20 chicks. The treatments were diets that contained 0, 1.5, or 3.0% DCSP. Treatments with added DCSP were fed for 3 wk, with the control diet fed the following 3 wk, or were fed continuously for 6 wk. At 42 d, the weights of the broiler were determined by pen. After slaughter and picking operations, the head and legs were removed. Broilers were eviscerated before determining empty body weight (EBW). Weights of the breast, leg, wings, abdominal fat, gizzard, liver and bile, heart and pancreas were determined. Finally, the different parts of the small intestine (duodenum, jejunum and ileum) were measured. Data analysis was performed using SAS software, and mean comparison was conducted using Duncan's multiple range test. The final weight (FW) was not significantly affected by treatment (P > 0.05). The mean EBW were not significantly different (P > 0.05). The mean carcass percentage was not significantly affected by treatment (P > 0.05). The mean breast percentage was significantly affected by treatment (P < 0.05). The lowest breast percentage was from broilers fed 1.5% DCSP from 1-42 d treatment and highest rate was concerned to treatment 3% DCSP 1st-21st day. The mean leg yield percentage between treatment was significantly different (P < 0.05). The lowest leg yield percentage was related to treatment 3% DCSP at 1st-42nd day and highest rate was concerned to treatment 1.5% DCSP 1st-21st day. The mean wing percentage between treatment was not significantly different (P > 0.05). The lowest wing percentage was related to treatment 3% DCSP at 1st-42nd day and highest rate was concerned to treatment 1.5% DCSP 1st-21st day. Discussion: Results from this study have been inconsistent with the findings of other researchers which show that broilers that were fed with a mixture of volatile oils of thyme, cumin, coriander, garlic and onion in four levels of (0, 20, 40 and 80 g/kg) did not differ significantly between treatments. Maximum weight of the legs and wings muscle was related to the treatment which had used the 1.5% DCSP 1st-21st day and the lowest was related to the treatment which had used 3% DCSP 1st-42nd day. Results of this study was conform with the findings of other authors who showed that broilers fed butyric acid in the diet has no effect on the relative weight of legs and breasts. As conclusion, experimental treatments on FW, EBW weight as well as carcass percentage of broilers during the finisher period was not significantly different (P > 0.05), but on carcass characteristics and also the jejunum and ileum during the finisher period was significantly different (P < 0.05).

Effects of two levels of quantitative feed restriction for a 7- or 14- days period on broilers blood parameters

Background: Compensatory growth after a feed restriction (FR) period, associated with increased feed intake and digestive adaptation allows the broilers chickens to demonstrate better food conversion efficiency and meat yield when submitted to an early-age food restriction. Differences in levels of feed restriction or on the period of feed restriction need to be adapted to each broilers strain, and should balance an adequate physiological response towards compensatory growth for production of the most suitable carcass, the smallest stress and an adequate immune-competence levels. So far, investigations showed considerable variations concerning broilers response to early life restrictions, physiological associate changes, compensatory growth and fat deposition. This experiment had been done to compare the effects of quantitative feed restriction imposed in different intensities and durations on the blood concentrations of energy, protein and lipid metabolites. Materials, Methods & Results: Five experimental treatments included T1 corresponded to controls (ad libitum); T2 and T4 groups were submitted to 25 and 50% feed restriction for one week; and T3 and T5 were feed deprived in 25 and 50% for two weeks, in three replicates of 10 pieces per treatment. Periods previous and subsequent (up to 42 days) to FR periods were fed ad libitum. All chickens were fed with ad libitum before and after the completion of the restriction period. Feeds were based on corn and soybean meal, and were formulated to contain the same protein and energy levels in all treatments; feed was adapted to the three main phases of the rearing period: the starter period (1-21 days of old), grower period (22-35 days old) and the finisher period (36-42 days old). At the end of the study, at 42 days of age, one bird per group, totalling 3 birds per treatment, was randomly selected for blood collection. Blood samples (1 mL/bird) were collected into EDTA tubes from the wing veins by the end of the experiment, at day 42. Samples were transferred to the laboratory for analysis within 2 h of collection. After centrifugation (3000 g, for 10 min at room temperature) plasma was harvested and stored in eppendorf tubes at -20ºC, until assayed. Severe restriction for a 2 week period showed the highest concentrations for Uric Acid (UAc), Triglycerides, VLDL, as well as the lowest for cholesterol and LDL; also, the highest ratios HDL/LDL were observed in this group, suggesting that birds in this treatment are more susceptible to protein catabolism during fasting and more prone to fat deposition in the carcass. In opposition, mild feed deprived birds showed the highest cholesterol and LDL concentrations in blood along with the lowest UAc, triglycerides and VLDL plasma values; they also showed lower HDL/LDL ratios than controls or severely feed deprived birds. No differences were observed between groups in glucose plasma concentrations. Discussion: The results suggest that feed restriction for longer periods may predispose the bird metabolism for an increased susceptibility for fat deposition, in comparison to the controls or the mild feed restriction treatments. Data gathered in the present study showed that quantitative feed restriction starting by day 8, followed by ad libitum was associated with changes in plasma metabolite concentrations. These changes varied between the two different intensities of FR and the two periods of FR evaluated. The results suggest that, for the same intensity of feed restriction, the length of deprivation may not be a determinant factor in mild FR. However, when severe FR is imposed, the length of FR may be a risk factor for excessive protein catabolism and increased VLDL availability, with the latter favouring precocious fattening of the carcasses. New studies are warranted to strength these results in particular on respect to the establishment of the influences of such changes in plasma metabolites with fatness and fat distribution on broilers.