A comparison of the quality of UHT milk and its plant-based analogs.

The aim of this study was to compare selected physical (density) and physicochemical (color, pH, titratable acidity) properties and the fatty acid profile of dairy UHT milk and its plant-based analogs, i.e., almond, soy, rice, oat, and coconut beverages. Ten products of each type were analyzed in each group. UHT milk was characterized by higher values of color lightness (L*) and titratable acidity than all plant-based milk alternatives, higher yellowness (b*) than rice drink, higher density than almond drink, and higher pH than rice and coconut drinks. In comparison with UHT milk, all plant-based beverages were characterized by higher redness (a*), soy drink was characterized by higher values of b* and chroma (C*), and almond and soy drinks had higher pH values. In the group of non-dairy beverages, the values of b* and C* were highest in soy drink, and the value of a* was highest in almond drink. Almond drink had the highest pH value, and soy and coconut drinks had the highest titratable acidity. Rice drink had higher density than oat, soy and almond drinks. The indicators characterizing the nutritional value of fat were considerably lower in coconut drink and dairy milk than in the remaining products. The values of UFA/SFA, MUFA/SFA, and DFA/OFA ratios and the indicator of nutritional value were highest in rice drink. The PUFA/SFA ratio and the total content of EFAs were highest in soy drink, and the n-6/n-3 PUFA ratio was highest in almond drink.

Effects of caponisation and age on the histology of the internal organs of Leghorn cockerels.

1. Poultry researchers seek the most efficient bird line to produce capons (castrated cockerels). The previous studies did not include results from histopathological analyses of internal organs after caponisation. No data have been published on whether adipose tissue accumulates in internal organs or if caponisation changes the structure of the lymphoid organs and the accumulation of lymphoid cells. 2. The aim of this study was to analyse the occurrence of histopathological lesions in internal organs from Leghorn (layer-type) capons and cockerels at different times of fattening. 3. Two hundred, one-day-old Leghorn cockerels were used in this experiment. At 8 weeks of age, the birds were randomly divided into a control group (100 uncastrated cockerels) and a second group consisting of 100 castrated birds. At 12, 16, 20, 24 and 28 weeks of age, six cockerels and six capons were slaughtered. Samples of all internal organs from six cockerels and six capons at each slaughter age were evaluated. 4. The main histopathological differences between capons and cockerels were related to the accumulation of adipose tissue, with higher values noted in capons, especially in the gizzard and the caecum submucosa and fatty degeneration in liver hepatocytes. 5. Additionally, differences were observed more often in cockerels than in capons with regard to depletion of lymphoid cells in lymphoid organs, including the thymus and bursa of Fabricius in 28-week-old birds and the spleen in 24-week-old birds. 6. These studies prove that caponisation causes the accumulation of fat in internal organs and changes the structure of lymphoid organs. 7. Age influences the occurrence of desirable lesions, such as the accumulation of adipose tissue within the examined organs, and older capons (24 and 28 weeks old) are better sources of high quality, potentially edible tissues.

Carcass characteristics, meat quality, and fatty acid composition of wild-living mallards (Anas platyrhynchos L.).

The aim of this study was to determine the carcass characteristics, meat quality, and fatty acid composition of wild-living mallards. The experimental materials comprised 30 mallards (1:1 sex ratio) harvested during the hunting season in northeastern Poland. The carcasses were transported to the laboratory where they were weighed individually, plucked, dressed, and dissected. The proximate chemical composition and physicochemical properties of meat and the fatty acid profile of breast muscle lipids were determined, and a histological analysis was performed. Body weight (BW) and carcass weight were higher in males than in females (P ≤ 0.05), whereas the percentage share of carcass tissue components was similar in both sexes. Edible components accounted for approximately 60% (♂) to 60.7% (♀) of the total BW of mallards, including lean meat; 40.9% (♂) to 41.5% (♀), skin with subcutaneous fat; 10.7% (♂) to 10.8% (♀), and giblets; 8.3% (♂) to 8.4% (♀). Breast muscles had high protein content (23.51%♀ to 23.6% ♂) and low fat content (0.82% ♂ to 0.84% ♀). In the fatty acid profile of breast muscle lipids, saturated fatty acids (SFA) accounted for 39.1% (♂) to 39.04% (♀), monounsaturated fatty acids (MUFA)-for 17.31% (♂) to 17.33% (♀) and polyunsaturated fatty acids (PUFA)-for 43.61% (♀) to 43.64% (♂). The diameters of type IIA and type IIB muscle fibers were lower in males than in females (P ≤ 0.05), whereas lipid storage sites in muscles were similar in both sexes. The values of cooking loss (CL), water-holding capacity (WHC), pH24, and color parameters of breast meat were comparable in males and females. The results of this study indicate that wild-living mallards, both males and females, are characterized by high meat quality, and that seasonal mallard harvests can provide meat with desirable eating attributes, attractive to consumers.

Effects of caponization and age on the histology, lipid localization, and fiber diameter in muscles from Greenleg Partridge cockerels.

The preference of modern consumers for high-quality meat has forced breeders to use native breeds to produce capons. Caponization, both chemical and surgical, leads to androgen deficiency and changes in lipid metabolism and results in the accumulation of abdominal, subcutaneous, and intramuscular lipids, which change the sensory values of the meat. The aim of this study was to histologically evaluate selected skeletal muscles from Greenleg Partridge capons and cockerels. We examined lipid localization in the muscular tissue and also assessed both fiber type and fiber diameter in the pectoral muscles. The experiment was performed on 200 Greenleg Partridge cockerels and testes were removed at 8 wk of age. At 12, 16, 20, 24, and 28 wk of age, 6 cockerels and 6 capons were slaughtered, and samples from the pectoral and thigh muscles were evaluated. Our histopathological evaluation revealed only minimal changes, and no significant differences between capons and cockerels were observed. The pectoral and thigh muscles of the capons had higher concentrations of lipids around the blood vessels, in the perimysium, in the endomysium, and in the sarcoplasm. The analysis of fiber type in the Pectoralis major muscles revealed that the fibers were all the IIB type. The diameters of the fibers of the pectoral muscles were significantly different (P < 0.05) at 20, 24, and 28 wk of age, and diameters of the giant fibers were significantly different (P < 0.05) at 24 and 28 wk of age. High concentrations of lipids in the meat of the capons is undesirable due to health-related reasons. However, the ability of adipose tissue to improve the sensory values of meat will always be a major quality of native/traditional products.

The effect of age and castration on the growth rate, blood lipid profile, liver histology and feed conversion in Green-legged Partridge cockerels and capons.

The surgical castration of male chickens induces hormonal changes, which permanently influence metabolic processes in birds. The aim of this study was to determine the effect of age and castration on the growth rate, feed conversion, lipid profile and histopathological changes in the livers of cockerels and capons. The experimental materials comprised male chickens of the Green-legged Partridge breed (old traditional Polish chicken breed), raised to 28 weeks of age. At 8 weeks of age, 100 birds were castrated. Caponization had a significant effect on the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triacylglycerols (P<0.05). Fatty degeneration and lymphoid cell infiltration were observed more frequently in the livers of capons than cockerels. Capon carcasses were characterized by increased deposition of abdominal and subcutaneous fat (P<0.05). Total meat weight in the carcasses of cockerels and capons was similar, but the proportions of muscles were different. From 20 weeks of age, the weight of breast muscles was higher, and the weight of leg muscles was lower in capons than in cockerels (P<0.05). Capons were characterized by higher liver weight, higher gizzard weight and lower heart weight than cockerels (P<0.05). The feed conversion ratio (kg/kg BW) was similar in intact cockerels and capons. The values of carcass quality parameters and feed conversion ratio as well as histopathological changes in the liver indicate that Green-legged Partridge capons should be slaughtered at 20 to 24 weeks of age.

Alternative growth functions for predicting body, carcass, and breast weight in ducks: Lomolino equation and extreme value function.

In this study, 2 alternative growth functions, the Lomolino and the extreme value function (EVF), are introduced and their ability to predict body, carcass, and breast weight in ducks evaluated. A comparative study was carried out of these equations with standard growth functions: Gompertz, exponential, Richards, and generalized Michaelis-Menten. Goodness of fit of the functions was evaluated using R(2), mean square error, Akaike information criterion, and Bayesian information criterion, whereas bias factor, accuracy factor, Durbin-Watson statistic, and number of runs of sign were the criteria used for analysis of residuals. Results showed that predictive performance of all functions was acceptable, though the Richards and exponential equations failed to converge in a few cases for both male and female ducks. Based on goodness-of-fit statistics, the Richards, Gompertz, and EVF were the best equations whereas the worst fits to the data were obtained with the exponential. Analysis of residuals indicated that, for the different traits investigated, the least biased and the most accurate equations were the Gompertz, EVF, Richards, and generalized Michaelis-Menten, whereas the exponential was the most biased and least accurate. Based on the Durbin-Watson statistic, all models generally behaved well and only the exponential showed evidence of autocorrelation for all 3 traits investigated. Results showed that with all functions, estimated final weights of males were higher than females for the body, carcass, and breast weight profiles. The alternative functions introduced here have desirable advantages including flexibility and a low number of parameters. However, because this is probably the first study to apply these functions to predict growth patterns in poultry or other animals, further analysis of these new models is suggested.

The effect of age on the growth rate of tissues and organs and the percentage content of edible and nonedible carcass components in Pekin ducks.

Age has a significant effect on carcass tissue composition, which is an important consideration in slaughter animals because age-related changes are observed in both edible and nonedible carcass components. In this study, the above changes were analyzed in Pekin ducks. The weight of individual edible and nonedible components in ducks increased for different periods of time, and the growth rate of tissue components varied considerably. The percentage content of edible components in the total BW of Pekin ducks increased from 42.8% in wk 1 to 59.9% in wk 8, mostly due to a significant (13.3%) increase in the share of muscle tissue. The percentage content of skin and subcutaneous fat remained at a stable level from wk 4, whereas the share of giblets decreased from 6 wk of age. The percentage content of nonedible components in the total BW of Pekin ducks decreased from 48.6% in wk 1 to 34.6% in wk 8, mainly due to a decrease in slaughter offal content (from 39.7% in wk 1 to 27.2% in wk 8). Minor changes were noted in the proportion of bones (11.7% in wk 1 and 10.9% in wk 8).

Use of a modified skin slice with subcutaneous fat and carcase weight without this slice for prediction of meatiness and fatness in young slaughter geese.

1. White Italian geese (40 males and 40 females) were reared until 12 weeks of age and fed standard diets ad libitum. After rearing ended, the geese were weighed (males-5216 g, females-4945 g) and killed. Carcases were chilled and skin slices with subcutaneous fat removed. The remaining part of the carcase was dissected into meat, intermuscular fat and bones. 2. The weight of a skin slice with subcutaneous fat, taken from the carcase surface excluding the forewings and wing tips (X2), and the weight of a carcase excluding this slice, the forewings and wing tips (X1) were very good indicators of the content of skin with fat (r > 0.99) and meat (r > 0.98) in a whole carcase. 3. The above traits provided a basis for deriving regression equations to estimate the content of meat (Y) or skin with subcutaneous and intermuscular fat (U) in whole carcases of White Italian geese. The following equations are recommended for practical application: Y = 0.755X1 - 27.8 (Sy = 26.3 g); U = 1.070X2 + 19.5 (Su = 11.4 g).

Prediction of meatiness and fatness in ducks by using a skin slice with subcutaneous fat and carcass weight without skin.

The experiment was performed on Pekin ducks (A-44 strain; 60 males and 60 females). The birds were reared to 7 wk of age and fed standard diets ad libitum. At the completion of the rearing period, the ducks were killed. The carcasses were chilled, and skin slices with s.c. fat were removed by a new method. The remaining part of the carcass was dissected into meat, intermuscular fat, and bones. The statistical analysis showed that the weight of a skin slice with s.c. fat, taken from the carcass surface excluding the forearms and wing tips [skin slice with fat (X(2))], and the weight of a carcass without this slice, forearms, and wing tips (X(1)) were very good indicators of the content of skin with fat (r = 0.99) and meat (r = 0.96), respectively, in a whole carcass. The above traits provided the basis for deriving regression equations to estimate the content of meat (Y) or skin with s.c. and intermuscular fat (U) in whole carcasses of ducks. The following 2 equations may be recommended for practical application: Y = 0.691 X(1) - 0.77 (S(y) = 21.6 g) U = 1.056 X(2) + 53.32 (S(u) = 10.6 g).

Age-related changes in the distribution of lean fat with skin and bones in goose carcasses.

The experimental materials comprised White Italian geese (128 males and 128 females) reared to 14 wk of age. The birds were fed standard diets ad libitum. Starting from 2 wk of age, 14 males and 14 females were killed at 2-wk intervals. The carcasses were divided into neck, wings, legs, breast, and back, which were then dissected into muscle, skin with fat, and bones. Before slaughter, the BW of males and females were 6,814 and 5,736 g, respectively. At 2 wk of age, more than half of total muscle content was in the legs (60.98%), and the rest was in the back (17.84%), neck (9.43%), breast (8.78%), and wings (2.97%). To 10 wk of age, the rate of muscle deposition was relatively slow in the legs (a decrease to 31.29%) and fast in the breast and wings (an increase to 34.12 and 12.90%, respectively). Age-related changes in the distribution of skin with fat in the carcass were smaller, compared with changes in muscle distribution. A rising tendency was observed in the muscle content of wings and breast and in the content of skin with fat in the wings and neck, whereas a falling tendency was observed in the other carcass parts. Over the first 8 wk, the proportion of bones decreased in the legs, back, and neck and increased in the wings and breast, as compared with the total bone weight in the carcass.

Age-related changes in the distribution of lean, fat with skin and bones in duck carcases.

The experimental birds were Pekin ducks (352 males and 352 females) reared to the age of 13 weeks. They were fed standard diets ad libitum. Starting from the second week, 21 males and 21 females were slaughtered every 7 d. Their carcases were divided into the following elements: neck, wings, legs, breast and back, which were then dissected into lean, skin with fat and bones. The body weights of one-day-old ducklings were similar (circa 62 g), but at 5 weeks of age the males were heavier than the females, and at 13 weeks of age their body weights were 3537 g and 2994 g, respectively. In 2-week-old ducks 55.77% of lean was located in the legs, 15.91% in the back part, 2.78% in the wings, 12.47% in the neck and only 13.12% in the breast. Considerable changes in the distribution of lean were noted in the ducks aged 7 weeks. Its percentage decreased in the legs (to 29.34%) and increased in the breast and wings (to 36.86% and 10.96%, respectively). Age-related changes in the distribution of skin with fat were smaller. Its percentage increased in the wings, legs and back, and decreased in the neck and breast. Until the age of 7 weeks the percentage of bones was decreasing quickly in the legs and increasing in the neck and breast, compared with their total weight in the carcase.