I. Herzig

Toxicological risk of melamine and cyanuric acid in food and feed

Toxicological risk of melamine and cyanuric acid in food and feed From the toxicological point of view, in the last two years melamine and cyanuric acid have become matters of great interest. These substances, especially melamine, have been abused during food and feed adulteration by increasing the content of nitrogen compounds in these products. Melamine and cyanuric acid as individual substances do not pose any serious risk in terms of toxicology. From the point of view of toxicology, it is especially the complex of melamine with cyanuric acid that is important. This complex, also known as the melamine-cyanurate complex, is a cause of human and animal health problems. In this work we present two examples of the incidence of melamine and cyanuric acid in two feed products originating from China. They were rice and the pea concentrates intended for animal nutrition. Protein concentrates can be the main risk factor for food chain contamination with melamine and cyanuric acid, especially those of unknown origin. Feed with a high content of nitrogen compounds and low content of aminoacids can be regarded as particularly suspicious. A comparison of results for determining nitrogen compounds and amines can be used as proof of adulteration of protein feeds. These feeds must be subjected to further analysis to determine melamine and cyanuric acid.

Long-term application of clinoptilolite via the feed of layers and its impact on the chemical composition of long bones of pelvic limb (femur and tibiotarsus) and eggshell

Selected 120 layers, hybrid breed Bovans Goldline, were divided into two balanced groups: control (C) and experimental (E) group. The layers were raised in three-floor cage technology with automatic watering, manual feeding, in the environment with regulated lighting and thermal schedule. The actual experimental period started in the 22 nd week and ended in the 68 th week of age of the layers. In the period following the filling of the cages the layers received complete feed mixture N1, subsequently, until the end of the experiment, they received feed mixture N2. The feed mixtures for Group C and E were of the same composition, with the only difference that the feed mixture designed for the experimental group contained 1% of clinoptilolite (commercial additive ZeoFeed) as a substitute for the same portion of wheat.. The layers consumed the feed mixtures and drinking water ad libitum. In the layers of Group E the intensity of egg laying increased by 1.1%, which corresponds to an increased number of laid eggs 3.08 per layer. The average weight of laid eggs was 66.3 ± 6.25 g in the layers of Group C, 65.6 ± 5.44 g (P ≤ 0.05) in the experimental layers of Group E. In Group E the consumption of feed mixture per one egg was 4.1 g lower when compared to the control. In 100% dry matter the eggshell of layers that received clinoptilolite (Group E), as opposed to Group C, had a statistically significantly higher ( P ≤ 0.01) content of crude protein, calcium and magnesium. Almost the same and insignificant difference in values was found in ash and phosphorus. The values of the same indicators were statistically significantly higher in both monitored bones (femur and tibiotarsus) (P ≤ 0.05; P ≤ 0.01) during the application of clinoptilolite (Group E), with the exception of P in femur, where an insignificant rise in the level of P occurred. The rise in the concentration of Mg in Group E was of particular importance: in femur by 50.4%, in tibiotarsus by 32.4%. If we compare the monitored values in femur and tibiotarsus, we can see that the levels of ash, Ca and P are higher in tibiotarsus, and the levels of crude protein and Mg are lower. The long-term application of clinoptilolite favourably influenced the lodgement of Ca, P, Mg and crude protein in the eggshell as well as in the bones ( femur, tibiotarsus), increased the egg production and reduced the consumption of feed mixture per one egg, while the good productive health of the layers was maintained.

Levels of fatty acids in the whole body of hens and cocks of the Cobb 500 and Ross 308 hybrid combinations at the end of the fattening period

In this study, we determined the levels of individual fatty acids in the whole chicken body, as well as dry matter, nitrogenic substances and fat in Cobb 500 and Ross 308 chickens after 40 days of fattening. The highest level of all fatty acids (FA), regardless of the hybrid combination and sex of the chickens, was determined for oleic/elaidic acid, followed by palmitic, linoleic/linolelaidic, palmitoleic and stearic acids. In Cobb 500 cocks, higher values (P ≤ 0.05; P ≤ 0.01) were found for all saturated fatty acids (SaFA) compared to hens. With the exception of γ-linoleic acid, the levels of n-6 FA measured in cocks were higher (P ≤ 0.01) than in hens and n-3 FA showed higher levels of eicosatrienoic (P ≤ 0.05) and docosapentaenoic acids (P ≤ 0.01). Ross 308 hens had higher levels of most SaFA, with differences for palmitic (P ≤ 0.01), myristic, heptadecanoic and stearic acids (P ≤ 0.05). Regarding monounsaturated fatty acids (MUFA), hens contained higher levels of myristoleic (P ≤ 0.05) and oleic/elaidic acids (P ≤ 0.01). Cocks showed higher levels of n-6 FA except for linoleic/linolelaidic and γ-linolenic acids; higher levels were found for cis-8,11,14-eicosatrienoic, docosatetraenoic (P ≤ 0.05) and arachidonic acids (P ≤ 0.01). With the exception of α-linolenic acid, n-3 FA levels were higher in cocks, with differences in the levels of cis-5,8,11,14,17-eicosapentaenoic and docosapentaenoic acids (P ≤ 0.01). The results suggest possible directions for future research focused on the use of broiler chicken hybrids with more favourable proportions of n-6 FA and n-3 FA in fat and meat.

Comparison of the content of crude protein and amino acids in the whole bodies of cocks and hens of Ross 308 and Cobb 500 hybrids at the end of fattening.

Dry matter (DM), crude protein (CP), and the content of individual amino acids (AA) were deter - mined in the bodies of Ross 308 and Cobb 500 hybrids including feathers after 40 days of fattening. Percentages for the content of individual AA were then calculated from the total sums of AA. The level of CP, irrespective of sex, was 453.16 ± 5.916 g/kg of DM for the Ross and 470.94 ± 5.404 g/kg of DM for the Cobb hybrid ( P ≤ higher values were found in cocks. Of the total sums of AA in DM of Ross broilers, the largest presence (here and after in %) was that of Glu (14.92), followed by Leu (8.80), Asp (8.73), Gly (8.71), Arg (7.21), Val (6.33), and Pro (6.09). The lowest contents were those of Met (2.41) and His (3.28). For the Cobb hybrid, the AA were Glu (13.90), Asp (9.12), Gly (8.48), Leu (8.43), Arg (7.48), Lys (6.44), and Pro (6.09). The AA lowest contents were those of Met (2.30) and His (3.16).

Amino acid levels in muscle tissue of eight meat cattle breeds.

Vopálenský J., Suchý P., Straková E., Šimek F., Macháček M., Herzig I. (2017): Amino acid levels in muscle tissue of eight meat cattle breeds. Czech J. Anim. Sci., 62, 339–346. Ten clinically healthy bulls equal in weight were chosen from eight meat cattle breeds maintained in the same geographical conditions using the extensive grazing method. After slaughtering, muscle tissue samples were taken from the musculus longissimus and pars thoracis, and dry matter, nitrogenous substances, fat, and the levels of essential (EAAs) and non-essential (NEAAs) amino acids were determined. Significant differences were found between the monitored genotypes in the contents of dry matter, nitrogenous substances, fat, EAAs, and NEAAs (P ≤ 0.05). The highest concentrations of nitrogenous substances in muscle tissue were detected in the Limousine breed and the lowest in the Aberdeen Angus breed; the highest fat content was found in Aberdeen Angus and the lowest in Galloway. Out of the total sum of EAAs, the highest percentage in the dry matter of muscle tissue in all genotypes was found for Lys (8.8–10.4%), the lowest percentage was found for Met (2.4–2.9%). The value of Thr was approximately 4.6, Val 5.1, Ile 4.8, Leu 8.2, Phe 4.1, His 4.2, and Arg 8.0%. Significant differences (P ≤ 0.05) between the monitored breeds were found in all EAAs, except for Val and Leu. Regarding NEAAs, out of the total protein, the highest percentage was found for Glu (13.9–15.1%). Conversely, the lowest values were detected for Ser (3.8–4.1%) and Tyr (3.8–4.4%). The values of other NEAAs were approximately 9.3 for Asp, 4.0 for Ser, 5.3 for Pro, 5.5 for Gly, and 6.1% for Ala. Significant differences (P ≤ 0.05) were found between the monitored genotypes in all NEAAs except for Pro and Ala. In the dry matter of muscle tissue, out of the total protein, the sum of EAAs ranged from 50.6 (Meat Simmental) to 52.0% (Limousine), and NEAAs ranged from 48.0 (Limousine) to 49.4% (Meat Simmental). Apart from its effect on the biological value of meat, representation of individual amino acids is important to enhance its taste or smell.

Levels of nitrogenous substances and amino acids in bodies of Ross 308 hybrid cocks and hens over the course of rearing

Over the course of Ross 308 hybrid broiler chick cock and hen rearing, whole chicken bodies includ - ing feathers were monitored for changes in the levels of nitrogenous substances, essential amino acids (EAA) and non-essential amino acids (NEAA). At five-day intervals (Days 1, 5, 9, 15, 20, 26, 30, 35 and 40 of rearing), randomly selected chickens were slaughtered after 24 h of fasting. Over the course of rearing, N-substance levels ranged from 629.1 to 429.0 g/kg dry matter in hen bodies and from 616.0 to 477.3 g/kg dry matter in cock bodies. N-substance levels were statistically significantly different in the two sexes on rearing Days 35 and 40 ( P ≤ 0.01). The levels of all amino acids (AA) in dry body matter of chickens up to 15 days of age dropped significantly over time, while in the period from Day 20 to Day 40, some AA levels increased or reached the baseline. With most AA, the levels were lower in hens than in cocks over the course of the trial. At the end of the trial (Days 35 and 40), statistically significant differences between the sexes were found for most EAA ( P ≤ 0.01; P ≤ 0.05). NEAA, except for Ser and Ala, were also significantly higher in cocks on Days 35 and 40 ( P ≤ 0.01; P ≤ 0.05). Among the monitored EAA, the dry matter of the bodies of hens exhibited the highest levels of Leu, 8.70% on average, followed by Val 6.54%, Lys 5.26%, Ile 5.25%, Thr 4.84%, Phe 4.30%, Tyr 2.51% and Met 2.21%. Leu was also the most abundant in the cock bodies, 8.42% on average, followed by Val 6.30%, Lys 5.36%, Ile 5.06%, Thr 4.57%, Phe 4.45%, Tyr 2.88% and Met 2.17%. Knowledge of the levels of nitrogenous substances, EAA and NEAA in the whole bodies of broiler chickens including feathers will help to determine optimal rearing conditions.