Monika Michalczuk

Comparison of Selected Quality Attributes of Chicken Meat as Affected by Rearing Systems

Abstract The objective of this study was to establish the effect of rearing conditions of slowly-growing Hubbard JA 957 chickens on selected quality attributes of their meat. Birds from the control group (C) were kept on litter over the entire rearing period, whereas these from the experimental group (E) - with access to free range since the 4th week of life. The birds were slaughtered on day 63, and collected samples of breast muscles were assayed for proximate chemical composition, technological properties, and fatty acid profile in intramuscular fat. The study demonstrated no significant differences in the chemical composition of muscles depending on rearing systems. Meat of chickens using free range was characterized by higher shear force (P≤0.01), which shows that it is tougher than the meat of chickens which do not use the free range. No significant differences were seen in physicochemical values when it comes to different systems of rearing. The access to free range has no influence on fatty acid formation either. The lack of significant differences indicates that the system of rearing has a minor effect on the quality of poultry meat.

Effect of packaging method and cold-storage time on chicken meat quality

This study was performed to determine the effects of vacuum packaging (VP) and modified-atmosphere packaging (MAP) (CO2/N2 = 3:7) on the physicochemical properties and sensory attributes in chicken breast meat during storage at 2ºC±0.5ºC for 5, 10 and 15 days. Results showed that storage time influenced the physicochemical properties, except sensory attributes, shear force and shear energy of chicken meat. The extended storage time was causing an increase in the pH value, drip loss and in values of color parameters (L, a* b*) in chicken meat. Moreover, the packaging method affected values of drip loss, cooking loss and shear force. Fresh meat (0 days of storage) was characterized by the highest overall quality assessed with the semi-consumer scaling method. Storage time and packaging method were found to exert significant effects on the physicochemical parameters determined instrumentally and on sensory attributes of meat evaluated with the semi-consumer scaling method.

Effects of a blend of essential oil compounds and benzoic acid on performance of broiler chickens as revealed by a meta-analysis of 4 growth trials in various locations

A series of growth trials with broiler chicks was conducted in various geographical locations to evaluate the efficacy of a novel eubiotic feed additive (EFA) at various dietary inclusion levels on performance of growing chicks. The EFA product consisted of a blend of essential oil compounds (thymol, eugenol, piperine) with benzoic acid, all belonging to the group of flavoring substances. Although variable in responses, the overall results indicated that 300 mg/kg of this EFA represented an optimum supplementation dose for generation of beneficial performance effects in broilers. A meta-analysis with all data from the 300 mg/kg EFA-supplemented treatments in comparison with the non-supplemented controls revealed that the eubiotic product significantly improved BW on d 21 (+2.0%; P = 0.0021) and on d 42 (+1.4%; P = 0.0151). Furthermore, the birds on the EFA 300 mg/kg treatment expressed a higher average daily gain in the starter phase (d 1-21; +2.1%; P = 0.0023) and over the entire experimental period (d 1-42; +1.5%; P = 0.0154). Feed conversion ratio was more favorable with dietary EFA supplementation (-0.6%; P = 0.0414), when compared with the control birds. Mortality was considered normal and was not affected by the dietary treatment (control = 3.09%; EFA 300 mg/kg = 3.26%). In conclusion, 300 mg/kg of this new eubiotic product demonstrated to effectively improve performance of broiler chicks under various husbandry conditions.

Early and 24 h post-mortem changes in breast muscle quality traits of two turkey genotypes and their reciprocal crosses raised under semi-confined conditions.

Abstract An experiment was conducted to determine the effect of reciprocal crossing of turkeys on early and 24 h post-mortem changes in quality traits of their breast muscles. The turkeys of slow-growing (SG) and fast-growing (FG) lines as well as SF (SG × FG) and FS crosses (FG × SG) were reared with access to free range. After slaughter turkey breast muscles were examined in the following terms: 5 min, 45 min, 2 h and 24 h post-mortem, for: temperature, pH, glycogen content (G), lactate content (L) and electrical conductivity (EC). Quality attributes of the breast meat were evaluated based on chemical composition, water holding capacity (WHC), cooking loss (%), shear force (N) and colour (L*, a*, b*). Despite differences in the rate of post-mortem changes, the genotype of turkeys had no significant effect upon many quality traits assessed 24 h post-mortem. Meat of lighter birds (SG and SF) was characterised by a lower fat content but a similar protein content compared to meat of FS and FG turkeys. In addition, meat of males from these groups was darker. Meat from the breast muscles of heavier birds (FS and FG) was harder. Significant negative maternal effects were determined for temperature of meat of both male and female turkeys, for pH2 and EC24 of males as well as for L2, L24 and cooking loss of female meat. Positive heterosis was confirmed only for pH2 of female meat and for G2 of male meat. In summary, the direction of fast- and slow-growing turkey crossing may affect the quality of their meat. However, meat of both types of hybrids reared under semi-confined conditions (with the possibility of using free range) was characterised by appropriate quality parameters.

Effect of linseed, rapeseed, and vitamin E long term supplementation on the activity of the lysosomal enzymes in ostrich liver

Abstract The aim of the study was to assess the activity of lysosomal enzymes: aminopeptidases, including alanine aminopeptidase (AlaAP), leucine aminopeptidase (LeuAP), arginine aminopeptidase (ArgAP), and glycosidases, such as β-galactosidase (BGAL), β-glucuronidase (BGRD), β-glucosidase (BGLU), N-acetyl-β-hexosaminidase (HEX), α-glucosidase (AGLU) and α-mannosidase (MAN) in the liver of ostriches (n = 80) fed diet supplemented with linseed (4% and 8%) and rapeseed (5% and 10%), with low and high level of vitamin E. (40 and 100 mg). The results indicate that higher level of vitamin E or 4% linseed supplementation in ostrich diet generally increase the activity of glycosidase enzymes and decrease the activity of aminopeptidases in the liver. The 8% linseed and rapeseeds feeding in decreased the activity of AlaAP, LeuAP, and ArgAP and increased only the activity of BGLU.

Comparsion of production performance of two genetic groups of turkeys reared in the Semi-intensive system

Production results were compared for two groups of turkeys reared in semi-intensive system. The material included 40 primitive turkeys of the light type and 40 heavy hybrids of the Big-6 line (commercial flock). Females was raised to 14 and males to 22 weeks of life. During the rearing, body weight (g) was controlled individually and feed intake (g) was monitored in groups, in weekly intervals. Significantly higher body weight values (P ≤ 0.01) were reported in both females (8806 g) and males Big-6 (23593 g), compared to primitive turkeys (2418 g and 6589 g, respectively). Big-6 turkeys were also characterized by a faster growth rate. This group compared to primitive turkeys showed also a higher feed intake and lower FCR values. Losses control of the turkeys throughout the rearing period showed a 17.5% increase in the survival rate in the group of primitive turkeys.

Influence of indoor and outdoor systems on meat quality of slow-growing chickens

ABSTRACT The aim of this study was to determine the effect of rearing system (with and without outdoor access) on carcass composition and meat quality in slow-growing chickens. The highest shear force was found for the breast muscles of chickens from the outdoor group. Breast (P < 0.05) and leg (P < 0.01) muscles of the birds from the outdoor group were characterized by the highest content of vitamin E. Therefore, differences were observed in fatty acid composition. A lower level of saturated fatty acid (SFA) (P < 0.01), a higher level of n-3 polyunsaturated fatty acid (PUFA) (P < 0.05), and a lower n-6/n-3 PUFA ratio (P < 0.01) were found in breast and leg muscles of chickens from the outdoor group. The breast muscles of chickens from the outdoor group were characterized by a higher level of monounsaturated fatty acids (MUFA) (P < 0.01) and a lower level of n-6 PUFA (P < 0.05). The rearing system may modify the health-promoting properties of meat.

Dietary vitamin E supplementation on cholesterol, vitamin E content, and fatty acid profile in chicken muscles

Abstract: The aim of the study was to determine the effect of dietary vitamin E level on cholesterol and vitamin E content and fatty acid profile in broiler chicken breast and leg muscles. Chickens (420 cocks) were randomly divided into two feeding groups (210 birds each). The control group was fed with standard diet containing 44 mg kg-1 of vitamin E, whereas the experimental group was supplemented with extra 200 mg kg-1 of vitamin E. The dietary addition of vitamin E caused a significant increase in its content in the muscles, with a higher value noted in the leg muscles. Meat of chickens fed with the higher dose of vitamin E was also characterized by a lower cholesterol level. The addition of vitamin E as well as type of the muscles had a significant effect on the fatty acid profile and values of atherogenicity (AI) and thrombogenicity (TI) indices. The recorded increase in the content of n-3 polyunsaturated fatty acids (PUFAs) and a decrease in the n-6/n-3 fatty acid ratio indicate a positive effect of vitamin E on the fatty acid profile. In turn, lower values of AI and TI in leg muscles of chickens with a high intake of vitamin E prove the beneficial fatty acid profile in these muscles upon such supplementation.

Variation in Growth Performance and Carcass Yield of Pure and Reciprocal Crossbred Turkeys

Abstract This study compared growth, feed conversion ratio (FCR), mortality rate and results of slaughter analysis of slow-growing Bronze turkeys (SG), fast-growing Big 6 turkeys (FG), and their reciprocal crosses (SF and FS). Until 6 weeks of age the birds were kept indoors and afterwards they were allowed to use free ranges. Toms were reared until 21 and hens until 15 weeks of age. The FS turkeys were characterized by higher (P≤0.05) BW and dressing percentage and by lower FCR compared to the SF crosses of both sexes. The analysis of orthogonal contrasts demonstrated that values of most of the slaughter analysis parameters were due to the additive effect of genes. Only weight of skin with fat and of gizzard could result from heterosis. Study results demonstrate that FS crosses constitute better material for the alternative production of turkeys compared to the other analysed groups (SG, SF, FG).

Early and 24 h post-mortem thigh (ilio tibialis) muscle metabolism and meat quality in two genetic types of turkeys and their reciprocal crosses, raised under semi-confined conditions

ABSTRACT 1. The experiment was conducted in order to determine the effect of the direction of turkey crossing on quality traits of their thigh muscle. 2. In total, 1358 turkeys of slow- (SG) and fast-growing (FG) lines as well as SF crosses (SG × FG) and FS crosses (FG × SG) were reared with access to free range to 21 weeks of age in the case of males and 15 weeks of age in the case of hens. 3. After slaughter of 15 males and 15 hens from each genetic line, their thigh muscles were examined and the following traits were measured after 5-min, 45-min, 2-h and 24-h post-mortem: temperature, pH, glycogen content (G), lactate content (L) and electrical conductivity (EC). Quality attributes were evaluated based on chemical composition, water holding capacity, cooking loss (%) and colour. 4. The rate of post-mortem changes in temperature, G, L and pH in muscles differed among the 4 lines of turkeys, with the highest metabolic rate determined for muscles of SG turkeys, followed by muscles of SF, FS and FG birds. A more beneficial muscle water holding capacity of both sexes of turkeys and better results of cooking loss in male muscles were found in SG and SF turkeys. The thigh muscles of the crosses were characterised by a higher content of protein and a lower content of fat compared to the muscles of FG turkeys, and in the case of the males also by a higher protein content compared to the muscles of SG birds. 5. Owing to the faster post-mortem metabolism, better water holding capacity, lower cooking loss and fat content at a similar content of protein, the thigh muscles of SF crosses raised in the free range system represent a better quality of meat for consumers compared to the thigh muscles of FS turkeys.