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Recent studies have shown vitamin levels above minimum requirements may optimize genetic potential and improve immune status. Optimum Vitamin Nutrition (OVNTM) is a new concept in animal nutrition that aims to better production and meat quality. The objective of this study was to evaluate the effects of different vitamin levels (NRC and OVNTM) in broiler diets on productive parameters and meat quality. A total of 3,840 1-d-old Cobb-500 chicks were assigned to 2 treatments with 12 replicates (floor pens) of 160 birds each in a randomized block design. Corn-soy diets were formulated according to the standards of Granja Tres Arroyos Company. Data was analyzed by ANOVA and Duncan’s multiple range test (α error=0.10). At the end of the trial, 44 days old, a significant increase (p≤0.10) in body weight (2.733 vs. 2.784kg) and daily weight gain (62.1 vs. 63.3g) was observed with OVNTM compared to NRC. The OVNTM treatment tended (p≤0.15) to present higher European production efficiency factor (342 vs. 354) than the NRC vitamin recommendation. The OVNTM treatment also showed higher (p≤0.05) level of alpha-tocopherol (8.0 vs. 20.6µg/g) in chicken meat, better (p≤0.05) oxidative protection (TBARS, up to -28.3% at 7 days of storage) and water retention capability (+10.6%) than with NRC recommendation. No differences were observed in pH and hardness. In conclusion, optimal vitamin supplementation could be successfully used to have better broiler performance and meat quality.
KEY WORDS: Tocopherol, Lipid peroxidation, Body weight, Water retention capability.
INTRODUCTION
Recent studies have shown vitamin levels above minimum requirements may optimize genetic potential and improve immune status. Optimum Vitamin Nutrition (OVNTM) is a new concept in animal nutrition that aims to better production and meat quality. The objective of this study was to evaluate the effects of different vitamin levels (NRC and OVNTM) in broiler diets on productive parameters and meat quality.
MATERIALS AND METHODS
A total of 3,840 1-d-old Cobb-500 chicks were assigned to two treatments with 12 replicates (floor pens) of 160 birds each in a randomized block design. The rearing period was 44 days. Pelletized feed was supplied ad-libitum. The treatments (Table 1) were T1: vitamin levels according to NRC (1994) and T2: OVNTM vitamin levels according to DSM Nutritional Products (Basel,Switzerland recommendations (DSM, 2004). The experimental diets were based on corn, soybean meal, steam deactivated full fat soybean and meat and bone meal. Diets were formulated according to the standards of Granja Tres Arroyos Company. At the end of the rearing period animal performance parameters (feed intake, body weight, daily weight gain, feed conversion ratio and European production efficiency factor (EPEF)) were analyzed. Meat quality (water retention capability, pH, hardness, TBARS and α-tocopherol content) was determined using a factorial arrangement, 2 treatments x 3 conservation times (1, 4 and 7 days).
pH: pHmeter Testo 230 with electrode for meat and automatic temperature compensated. (Boccard et al., 1981)
Hardness: Warner Bratzler shear over INSTRON mod. 4442 equipment. Cylindrical samples (Ø:1 cm), cell of50 kg, blade speed: 90 mm/min. Charge=maximum force at time of cutting (kgf).
Water retention capability: Through pressure between plates. (Grau and Hamm, 1957)
Lipid oxidation: Estimated by TBARS (Thiobarbituric Acid Reactive Substances) (Gray, 1978; Melton, 1983; Robards et al., 1988). Data is shown as μg of malonaldehide per Kg of meat.
Alpha-tocopherol: Determinates at day 1 of conservation from frozen chicken meat. Samples were extracted with hexane and separated by HPLC with fluorescence detection (λexc 296 nm- λem 330 nm). Calibration curve was performed with the standard of alpha-tocopherol (Merk,Germany).
Data was subjected to ANOVA. Means separation was performed using Duncan’s multiple range test (Balzarini et al., 2008). Statistical significance was considered at p≤0.10.
Table 1. Vitamin level per metric ton of feed
RESULTS AND DISCUSSION
Animal performance results are summarized in Table 2 and meat quality in Table 3.
Table 2. Animal performance results at 44 days old
At the end of the rearing period (44 days) chickens from OVNTM treatment were 1.86% heavier than NRC chickens (p≤0.10) and tend (p≤0.15) to have better EPEF and BW/FCR ratio.
Table 3. Meat quality of breast at different conservation times
The OVNTM treatment reaches the highest level of alpha-tocopherol in frozen meat, giving a differentiated quality product.
The higher presence of antioxidants such as alpha-tocopherol in poultry meat not only helps to preserve their organoleptic characteristics (Kennedy et al., 2005), but also this benefit is transferred to the consumer with the consequent improvement in oxidative status and health. (Di Mascio et al., 1991; Diplock, 1991)
No differences were observed in crude pH, cooked pH and hardness; but an improvement (10.6%) was observed in the water retention capability with OVNTM.
The meat quality (water retention capability and pH) decreased with the conservation time.
CONCLUSIONS
Chickens from OVNTM treatment were 1.86% heavier than NRC ones.
The OVNTM treatment reaches 156% more α-tocopherol content than NRC.
The OVNTM treatment increases the oxidative protection and water retention capability.
No differences were observed in crude pH, cooked pH and hardness.
In conclusion, optimal vitamin supplementation could be successfully used to improve broiler performance and meat quality.
BIBLIOGRAPHY
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