An important issue in poultry farming is the increased susceptibility of the animals to oxidative stress related to the increasing genetic selection toward larger breast muscles, increased body weights, and faster growth rates. Vitamin E as a potent natural antioxidant, is a well-established micro-nutrient used in animal nutrition to sustain animal health and production, and to reduce the oxidative processes in meat. Studies have also reported inhibitory effects of vitamin E on formation of carcinogenic compounds during meat processing. However, these tests mainly involved the less standardised inclusion of vitamin E in animal feeds or the topical application of vitamin E for marination of meat. The present study, therefore, aimed at assessing the effect of intramuscular vitamin E injection on growth performance, meat quality and safety of processed meat of Cobb 500 broiler chickens reared under tropical conditions in Uganda. The study was carried out in a small chicken farm in Uganda. Thirty, 28d old Cobb 500 chicks were randomly assigned to 3 treatment groups (5 replications/group), which were intramuscularly injected on left pectoral muscle with 0.25 mL (12.5 IU) (T1) and 0.5 mL (25 IU) (T2) of dltocopheryl acetate (50 mg/mL), and 0.5 mL of physiological saline (C). At 42d, birds were individually weighed, slaughtered and the pectoral muscle (PM) was removed for the analyses regarding physico-chemical properties, oxidative stability and detection and quantification of carcinogenic compounds. Data were analyzed by one-way ANOVA. Data for concentration of polycyclic aromatic hydrocarbons (PAHs) that did not meet the assumptions for ANOVA were analyzed using the Kruskal Wallis H test. The results indicate that i.m. vitamin E injection did not have significant effect on the final live weights of the birds. However, carcass yield was higher (P < 0.01) in T2 (71%) and T1 (69%) groups compared with C group (64%). The weights and yields of the main commercial cuts were similar among groups. Ultimate pH of PM was not significantly affected by vitamin E treatment; while higher doses of vitamin E (T2) improved the water holding capacity of PM (P<0.01). Total lipids, ranging from 2.13% to 2.25%, were similar among groups. In general, vitamin E treatment improved the oxidative stability of PM; the levels of TBARS were lower (P < 0.05) in T2 (0.037 mg MDA/kg) than in C group (0.046 mg MD/kg). The mean concentrations (g/kg) of PAHs formed in grilled meat were in the range: 0.30 – 1.55 for Benzo(a) pyrene, 0.37 – 2.54 for Benzo(b) fluoranthene, 0.80 – 1.19 for Benzo(g,h,i) perylene, 0.89 – 1.97 for Benzo(k) fluoranthene, 0.94 for Dibenzo(a, h) anthracene and 1.18 – 1.57 for Indeno (1,2,3-cd) pyrene. This research has shown that whereas there appears to be no significant effect of the treatment with vitamin E on formation of PAHs during grilling of broiler PM, an apparent trend towards inhibition of the formation of these carcinogenic compounds appeared to have emerged. This was evidenced by the fact that more of the compounds were detected in C as opposed to the vitamin E injected groups. The results from the Toxic Equivalent computation also revealed that the concentrations of the compounds detected were within the tolerable limit set by EU Regulation 835/2011 still in force. It should be noted that this attempt to investigate the inhibitory effect of i.m vitamin E injection on the formation of carcinogenic compounds in broilers has been probably the first; therefore, further research is required to obtain more information, regarding also the adequate dose of vitamin E to be injected.
L’intensa selezione genetica ha consentito negli anni di ottenere polli sempre più pesanti nel minor tempo possibile, rendendo gli animali maggiormente suscettibili allo stress ossidativo. La vitamina E, un potente antiossidante naturale, è un micronutriente utilizzato nell'alimentazione animale per migliorare lo stato di salute e la qualità delle produzioni, nonché per ridurre i processi ossidativi nella carne. Recenti studi, hanno dimostrato come la vitamina E, attraverso la marinatura della carne, sia in grado di inibire la formazione di composti cancerogeni in seguito a cottura ad elevate temperature. Il presente lavoro di tesi ha inteso valutare gli effetti della somministrazione di vitamina E per via intramuscolare sulle performance di crescita, sulle caratteristiche qualitative della carne e sulla formazione di sostanze cancerogene nella carne di polli Cobb 500 allevati in condizioni di clima tropicale in Uganda. Al 28° giorno d’età, 30 polli Cobb 500 sono stati suddivisi a random in 3 gruppi sperimentali (5 replicazioni/gruppo) trattati per via intramuscolare (muscolo pettorale sinistro) con: 0.25 mL (12.5 UI) (T1) e 0.50 mL (25 UI) (T2) di dl- α-tocopheril acetato (50 mg/mL), e 0.50 mL di soluzione fisiologica (C). Al 42° giorno d’età, i polli sono stati pesati, macellati e il muscolo pettorale è stato prelevato per le analisi riguardanti le proprietà fisico-chimiche, stabilità ossidativa e formazione di sostanze cancerogene. I dati ottenuti sono stati analizzati mediante ANOVA ad una via. I dati riguardanti la concentrazione delle idrocarburi policiclici aromatici (IPA) non rientranti nelle assunzioni dell’ANOVA sono stati analizzati mediante test di Kruskal Wallis. Il trattamento non ha avuto alcun effetto (P > 0,05) sul peso finale degli animali; tuttavia, i polli dei gruppi trattati hanno mostrato rese in carcasse maggiori (T2: 71% e T1: 69%; P < 0,01) rispetto al gruppo C (64%). Il peso e la resa dei principali tagli commerciali sono risultati simili tra i gruppi sperimentali. Il pH ultimo non è stato influenzato dal trattamento; mentre, la dose più alta di vitamina E (T2) ha determinato un aumento della capacità di ritenzione idrica del petto (P < 0,01). Il contenuto di lipidi totali (2,13 - 2,25%) è risultato simile tra i gruppi sperimentali. I livelli di TBARS (mgMDA/kg) sono risultati inferiori (P<0,05) nel gruppo T2 (0,037) rispetto al gruppo C (0,046). Le concentrazioni medie (μg/kg) di IPA formatesi durante la cottura alla griglia della carne rientravano nei seguenti range: 0,30 – 1,55 Benzo(a)pirene, 0,37 – 2,54 Benzo(b)fluorantene, 0,80 – 1,19 Benzo(g,h,i)perilene, 0,89 – 1,97 Benzo(k)fluorantene, 0,94 Dibenzo(a,h)antracene e 1,18 – 1,57 Indeno(1,2,3-cd)pirene. Questa ricerca ha dimostrato che, nonostante il trattamento con vitamina E non abbia avuto alcun effetto statisticamente significativo sulla concentrazione degli IPA, è evidente una tendenziale inibizione della formazione di questi composti in seguito a cottura della carne. Questa assunzione deriva dal fatto che la maggior parte dei composti sono stati rilevati nel gruppo C e non nei gruppi vitamina E. I dati relativi alla tossicità equivalente hanno evidenziato che le concentrazioni dei composti rilevati rientrano nei limiti di legge in vigore (Reg. UE 835/2011). Lo studio sull'effetto dell'iniezione intramuscolare di vitamina E sulla formazione di composti cancerogeni nei polli da carne è stato probabilmente il primo; sono quindi necessarie ulteriori ricerche per ottenere maggiori informazioni, anche riguardo alla dose adeguata di vitamina E da iniettare.
Effect of intramuscolar vitamin E injection on performance, meat quality and food safety of Cobb 500 broiler chickens reared under tropical climatic conditions
ONGWECH, ACAYE
2019-06-10
Abstract
An important issue in poultry farming is the increased susceptibility of the animals to oxidative stress related to the increasing genetic selection toward larger breast muscles, increased body weights, and faster growth rates. Vitamin E as a potent natural antioxidant, is a well-established micro-nutrient used in animal nutrition to sustain animal health and production, and to reduce the oxidative processes in meat. Studies have also reported inhibitory effects of vitamin E on formation of carcinogenic compounds during meat processing. However, these tests mainly involved the less standardised inclusion of vitamin E in animal feeds or the topical application of vitamin E for marination of meat. The present study, therefore, aimed at assessing the effect of intramuscular vitamin E injection on growth performance, meat quality and safety of processed meat of Cobb 500 broiler chickens reared under tropical conditions in Uganda. The study was carried out in a small chicken farm in Uganda. Thirty, 28d old Cobb 500 chicks were randomly assigned to 3 treatment groups (5 replications/group), which were intramuscularly injected on left pectoral muscle with 0.25 mL (12.5 IU) (T1) and 0.5 mL (25 IU) (T2) of dltocopheryl acetate (50 mg/mL), and 0.5 mL of physiological saline (C). At 42d, birds were individually weighed, slaughtered and the pectoral muscle (PM) was removed for the analyses regarding physico-chemical properties, oxidative stability and detection and quantification of carcinogenic compounds. Data were analyzed by one-way ANOVA. Data for concentration of polycyclic aromatic hydrocarbons (PAHs) that did not meet the assumptions for ANOVA were analyzed using the Kruskal Wallis H test. The results indicate that i.m. vitamin E injection did not have significant effect on the final live weights of the birds. However, carcass yield was higher (P < 0.01) in T2 (71%) and T1 (69%) groups compared with C group (64%). The weights and yields of the main commercial cuts were similar among groups. Ultimate pH of PM was not significantly affected by vitamin E treatment; while higher doses of vitamin E (T2) improved the water holding capacity of PM (P<0.01). Total lipids, ranging from 2.13% to 2.25%, were similar among groups. In general, vitamin E treatment improved the oxidative stability of PM; the levels of TBARS were lower (P < 0.05) in T2 (0.037 mg MDA/kg) than in C group (0.046 mg MD/kg). The mean concentrations (g/kg) of PAHs formed in grilled meat were in the range: 0.30 – 1.55 for Benzo(a) pyrene, 0.37 – 2.54 for Benzo(b) fluoranthene, 0.80 – 1.19 for Benzo(g,h,i) perylene, 0.89 – 1.97 for Benzo(k) fluoranthene, 0.94 for Dibenzo(a, h) anthracene and 1.18 – 1.57 for Indeno (1,2,3-cd) pyrene. This research has shown that whereas there appears to be no significant effect of the treatment with vitamin E on formation of PAHs during grilling of broiler PM, an apparent trend towards inhibition of the formation of these carcinogenic compounds appeared to have emerged. This was evidenced by the fact that more of the compounds were detected in C as opposed to the vitamin E injected groups. The results from the Toxic Equivalent computation also revealed that the concentrations of the compounds detected were within the tolerable limit set by EU Regulation 835/2011 still in force. It should be noted that this attempt to investigate the inhibitory effect of i.m vitamin E injection on the formation of carcinogenic compounds in broilers has been probably the first; therefore, further research is required to obtain more information, regarding also the adequate dose of vitamin E to be injected.| File | Dimensione | Formato | |
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