RESUMEN
Feather pecking is a serious economic and welfare problem in laying hens. Feather damage occurs mainly through severe feather pecking (SFP). Selection experiments have proved that this behavior is heritable and lines have been divergently selected for high (HFP) and low feather pecking (LFP). The number of bouts of SFP per hen follows a Poisson distribution with a maximum nearby 0. A few studies indicate that the distribution within flocks is not homogenous but contains sub-groups of birds showing extremely high levels of feather pecking (EFP). It was the aim of the current study to re-analyze data on SFP of lines selected for HFP/LFP and their F2 cross so as to uncover hidden sub-populations of EFP birds. Data of seven selection generations of HFP and LFP selection lines as well as their F2 cross have been used. We fitted a two-component mixture of Poisson distributions in order to separate the sub-group of EFP from the remaining birds. HFP and LFP lines differed mainly in mean bouts per bird. The proportion of EFP was only marginal in the LFP as compared with the HFP and the F2 population. Selection for LFP did not result in total elimination of EFP. The presence of even small proportions of EFP may play an important role in initiating outbreaks of feather pecking in large flocks. Further studies on feather pecking should pay special attention to the occurrence of EFP sub-groups.
Asunto(s)
Agresión/fisiología , Conducta Animal/fisiología , Pollos/fisiología , Bienestar del Animal , Animales , Plumas , Femenino , OvulaciónRESUMEN
1. Research in the field of poultry meat quality has become more varied during the last 50 years. Besides meat content and microbial condition, animal welfare issues during the slaughter process, muscle morphology, physiology of meat ripening, impact of slaughter process on meat quality, sensory attributes of meat and meat processing have come into focus. 2. The present review summarizes findings and developments in the fields of muscle physiology, meat ripening and meat quality aberrations (like PSE), nutrient composition and sensory qualities, effect of the slaughter process on carcass and meat quality, hygienic conditions and product safety during slaughtering, all based on selected papers published in British Poultry Science during the last 50 years. 3. Some special findings and conclusions are lifted out of the whole results presented in the papers to indicate their importance and to show their contribution to the development of knowledge in the respective field.
Asunto(s)
Carne , Aves de Corral/fisiología , Crianza de Animales Domésticos , Animales , Microbiología de Alimentos , Inocuidad de los Alimentos , Valor Nutritivo , Aves de Corral/genética , Aves de Corral/microbiología , InvestigaciónRESUMEN
The present study reports about the plasma carotenoid levels of chickens achieved after feeding diets containing free and esterified lutein (from marigold) and capsanthin (from red pepper) by applying HPLC analyses using a RP-C30 column. Forty chickens were divided at random into four groups and were fed 2 wk with different diets after receiving a basal diet with a low carotenoid content for carotenoid depletion (3 wk). One group was fed a diet containing free lutein (G1), another group received a diet with esterified lutein (G2), two other diets contained free (R1) and esterified capsanthin (R2), respectively. To unequivocally identify plasma carotenoids, liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry analysis was applied, which had never been used as an analytical tool to evaluate the carotenoids of chicken plasma; HPLC chromatograms of chicken plasma following capsanthin feeding have not been presented. The study showed that not only lutein but also capsanthin appeared in the blood stream after feeding free or esterified xanthophylls, demonstrating that capsanthin esters were bioavailable. Quantitative analysis showed comparable concentrations of plasma lutein and capsanthin, respectively, no matter if free or esterified carotenoids were fed.
Asunto(s)
Carotenoides/administración & dosificación , Carotenoides/sangre , Pollos/sangre , Dieta , Luteína/administración & dosificación , beta Caroteno/análogos & derivados , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Disponibilidad Biológica , Carotenoides/farmacocinética , Pollos/fisiología , Cromatografía Líquida de Alta Presión , Cromatografía Liquida , Criptoxantinas , Esterificación , Femenino , Alimentos Fortificados , Luteína/sangre , Espectrometría de Masas , Xantófilas , Zeaxantinas , beta Caroteno/sangreRESUMEN
We assessed the effect of a diet supplemented with fish oil (FO) on the performance, fatty acid (FA) composition, quality, and sensory traits of broiler meat. Diets enriched with 0, 2, or 4% FO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to the birds throughout a 38-d growth period. T3 was replaced by a mixture of FO, linseed oil (LO), and T (1, 3, and 4% respectively) for 1 wk (T4) or 2 wk (T5) before slaughter. Meat quality, taste, and FA profile were determined. Higher final weights were recorded for birds fed T3, although feed efficiency was not affected. Other performance or objective meat quality parameters did not show significant differences among treatments. High FO concentrations decreased the saturated and monoenoic FA contents in the thigh samples. The amount of polyunsaturated fatty acids (PUFA) increased when added to the diet (FO diets), mainly as long-chain n-3 FA [eicosapentaenoic fatty acid (EPA), docosapentaenoic fatty acid (DPA), and docosahexaenoic fatty acid (DHA)]. On the other hand, levels of total n-6 FA resulted in slight changes, mostly in linoleic acid (LA). By replacing the FO diet with the experimental mixture (T4, T5), the n-3 and n-6 FA contents increased, mainly in the form of linolenic acid and LA, respectively, only 1 wk later. After 1 wk of T4, the DHA levels in chicken decreased. Sensory panelists could not identify the meats from T4 and T5 as being different from the control diet (T1).
Asunto(s)
Pollos/crecimiento & desarrollo , Ácidos Grasos Omega-3/análisis , Aceites de Pescado/administración & dosificación , Carne/normas , Alimentación Animal , Animales , Grasas Insaturadas en la Dieta/administración & dosificación , Grasas Insaturadas en la Dieta/metabolismo , Ácidos Docosahexaenoicos/análisis , Ácido Eicosapentaenoico/análisis , Ácidos Grasos Omega-3/metabolismo , Ácidos Grasos Omega-6 , Ácidos Grasos Insaturados/análisis , Ácidos Grasos Insaturados/metabolismo , Aceites de Pescado/metabolismo , Aceite de Linaza/administración & dosificación , Aceite de Linaza/metabolismo , Carne/análisis , Distribución Aleatoria , Gusto , Aumento de Peso/efectos de los fármacosRESUMEN
To assess the effect of supplying linseed oil (LO) in the diet on performance, fatty acid (FA) composition, and quality objective parameters of broiler meat, diets enriched with 0, 2, or 4% LO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to broiler chickens throughout a 38-d growth period. T3 birds were slaughtered at 24 or at 52 d of age to study the effect of feeding time on FA accumulation in tissue. Objective and subjective evaluations of meat quality were performed on samples from 38-d-old birds, and the FA profiles of thigh and liver samples were determined. Performance parameters showed little difference between treatments. The differences in carcass yield values or in the objective quality parameters of the meat between treatments were not significant. Increased levels of LO clearly decreased the saturated (SAT) and monounsaturated FA (MUFA) contents. LO increased the amount of polyunsaturated FA (PUFA), mainly because of the linolenic (LNA) and linoleic (LA) acid content in the T3 samples, but they hardly reflected the wide range given in the experimental diets. The n-3 long-chain (LC) PUFA content of T3 thighs was slightly higher than in T1 thighs. Unexpectedly, longer feeding time of LO diets did not result in peripheral tissue accumulation of n-3 LC-PUFA, although chickens could convert LNA to longer-chain metabolites in liver at 24 d of age.
Asunto(s)
Pollos/crecimiento & desarrollo , Ácidos Grasos Omega-3/análisis , Aceite de Linaza/administración & dosificación , Carne/normas , Alimentación Animal , Animales , Grasas Insaturadas en la Dieta/administración & dosificación , Grasas Insaturadas en la Dieta/metabolismo , Grasas/administración & dosificación , Grasas/metabolismo , Ácidos Grasos Omega-3/metabolismo , Aceite de Linaza/metabolismo , Carne/análisis , Distribución Aleatoria , Gusto , Factores de Tiempo , Aumento de Peso/efectos de los fármacosRESUMEN
An experiment was carried out to examine thoroughly the relationships among different n-3 and n-6 polyunsaturated fatty acids (PUFA) in the diet, their deposition into the eggs' fat, and their effect on hens' laying performance. A diet enriched with 4% fish oil (FO) was fed to the birds throughout the 14-wk laying period (Treatment 1; T1); this was the same oil source that was replaced in proportions of 25, 50, 75, or 100% with four different fat sources, resulting in 17 isocaloric dietary treatments: linseed oil (LO; T2 to T5), rapeseed oil (RO; T6 to T9), sunflower oil (SO; T10 to T13), and tallow (T; T14 to T17). Performance parameters were recorded weekly and analyzed on the basis of the replacing fat source. At the end of the 14-wk experimental period, eggs were collected, and their fatty acid (FA) profile was determined. Performance parameters were not significantly different among grouped treatments. Smaller proportions of FO in diets resulted in lower values of saturated and higher values of n-6 FA contents, regardless of the fat source used when replacing FO. The n-6 content increased mostly because of the rise in linoleic acid (LA), although the level of arachidonic acid (AA) was always higher when FO was completely suppressed. The amount of the different n-3 long-chain PUFA was lower (P < 0.001) when FO was present in lesser proportions in the diet. However, the slope of the decline of these FA changed according to the included fat. Replacing FO with LO resulted in the lowest decline of its derivatives by elongation and desaturation and an increase in the total n-3 FA in the form of linolenic acid (LNA).
Asunto(s)
Pollos/metabolismo , Grasas de la Dieta/administración & dosificación , Huevos/análisis , Ácidos Grasos Insaturados/metabolismo , Animales , Yema de Huevo/química , Grasas/administración & dosificación , Ácidos Grasos/análisis , Ácidos Grasos Monoinsaturados , Ácidos Grasos Omega-3/administración & dosificación , Ácidos Grasos Omega-6 , Ácidos Grasos Insaturados/administración & dosificación , Ácidos Grasos Insaturados/análisis , Femenino , Aceites de Pescado/administración & dosificación , Aceite de Linaza/administración & dosificación , Lípidos/análisis , Oviposición , Aceites de Plantas/administración & dosificación , Aceite de Brassica napus , Aceite de GirasolRESUMEN
Two sequential experiments were conducted to assess the effect of replacing a fish oil diet with vegetable oil diets on broiler chicken performance and fatty acid (FA) composition and sensory traits of broiler meat. A diet enriched with 8.2% fish oil (FO) was fed to the birds throughout the 5-wk growth period (T1), the same basal diet being supplemented with 8.2% linseed oil (LO, Experiment 1) or rapeseed oil (RO, Experiment 2) in three different periods: the last week before slaughtering at 35 d (T2), the last 2 wk (T3), and throughout the experiment (T4). A sensory evaluation of the meat was carried out and its FA profile was determined. Performance parameters were not significantly different among treatments. Removing FO resulted in lower values of saturated and higher n-6 FA content, the latter because of the increase in linoleic acid in both experiments. The amounts of long-chain n-3 polyunsaturated fatty acids (PUFA) were significantly depressed when FO was replaced. However, replacing FO by LO resulted in minimal effects on total n-3 FA, due to the increase in linolenic acid. The substitution of FO by RO resulted in a decrease in the n-3 FA content, whereas levels of monounsaturated FA (MUFA) increased in direct relation to the larger amounts of oleic acid in the diet. Sensory panelists scored as unacceptable those meats from T1 in both experiments. Replacing 1 (T2) or 2 (T3) wk FO with vegetable oil clearly resulted in the improved sensory quality of meat.
Asunto(s)
Alimentación Animal , Pollos , Aceites de Pescado , Carne/normas , Aceites de Plantas , Animales , Ácidos Grasos/análisisRESUMEN
Broilers were reared on two flooring systems: conventional litter (wood shavings) and plastic floor ("trampoline") without litter. Female birds were housed over 49 d (20 birds per m2), males over 70 d (10 birds per m2). After slaughtering the guts were sampled and deep frozen. Guts of 84 birds from litter floor and 94 birds from plastic floor were examined for Salmonella. Totally, 20% of the guts were Salmonella negative. The plastic floor did not significantly diminish the occurrence of Salmonella. Also not significant in both flooring systems was the higher amount of negative samples after 49 d than after 70 days. Data show, that the amount of Salmonella in the guts of birds from plastic-floor might have been lower than those from litter-floor, in the samples from plastic-floor the amount of Salmonella after 49 days might have been lower than in those after 70 days rearing. The isolates were S. virchow and S. enteritidis.
Asunto(s)
Pollos/microbiología , Pisos y Cubiertas de Piso , Intestinos/microbiología , Salmonella/aislamiento & purificación , Animales , Femenino , Masculino , Enfermedades de las Aves de Corral/prevención & control , Salmonelosis Animal/prevención & controlRESUMEN
German Landrace pigs (n = 1500) were halothane-tested and blood samples were taken for the determination of A-O and H blood types as well as for the determination of PHI and 6-PGD isozymes. The pigs originated from two generations (7th and 8th) of a selection experiment 'selection for activity of NADPH-generating enzymes in backfat of pigs'. The selection lines are E-, E+ (selection for low and high enzyme activity), U- (selection for low ultrasonic backfat thickness) and K (control). Preliminary results show an average proportion of halothane-susceptible animals of 49%. The frequencies of halothane-positive pigs amount to 60%, 46%, 70% and 30% in lines E-, E+, U- and K, respectively. The investigation shows a non-random combination of the marker genes caused by linkage disequilibrium, especially in line E-. Recombination frequencies between the loci vary from 0% to 18%.