Effect of conjugated linoleic acid in the diet on performance and meat quality of broilers

Osnovni cilj istraživanja u okviru ove doktorske disertacije je bio da se ispita uticaj konjugovane linolne kiseline (conjugated linoleic acid-CLA) na proizvodne rezultate (potrošnja hrane, prirast, konverzija), parametre mesnatosti (pocenat mesa u trupu) i kvalitet mesa brojlera (hemijski sastav, senzorne osobine, masnokiselinski sastav, uključujući sadržaj CLA, sadržaj malondialdehida). Za ogled su korišćeni brojleri Cobb 500 provenijencije podeljeni u četiri grupe po 30 životinja i hranjeni standardnim smešama po preporuci proizvođača, s tim što su se grupe razlikovale jedino u tome što su ogledne grupe imale u obroku dodat komercijalni preparat konjugovane kiseline, u preporučenoj količini od 2% u smeši u različitim fazama tova (O-I grupa 2% CLA od početka tova, O-II grupa 2% CLA od 11. dana tova, O-III grupa 2% CLA od 22. dana tova) i kontrolna grupa (K grupa) bez dodatka CLA. Smeše su bile izbalansirane i u potpunosti zadovoljavale potrebe životinja u svim fazama tova. Na kraju tova životinje su izmerene, izračunata je potrošena količina hrane, a na klanici uzeti uzorci masnog tkiva i mesa za hemijske analze (hemijski sastav mesa, MDA i masnokiselinski sastav) i senzorne analize. Uzorci mesa bataka sa karabatakom za određivanje sadržaja MDA zamrznuti su pri -18oC. Na klanici su posle rasecanja izmerene mase osnovnih delova (grudi, batak sa karabatakom) trupa. Kod izoenergetskih i izoproteinskih smeša za ishranu brojlera utvrđene su statistički značajne razlike između prosečnih sadržaja zasićenih, mononezasićenih, polinezasićenih, n-3 i n-6 masnih kiselina. Utvrđena je statistički značajna razlika između odnosa n-3 i n-6 masnih kiselina. Prosečan ukupan sadržaj konjugovane linolne kiseline u smeši za ishranu oglednih grupa brojlera bio je 4,43 %. U hrani za kontrolnu grupu brojlera nije utvrđeno prisustvo konjugovane linolne kiseline. Na početku tova, a zatim na kraju prve i druge faze tova, kao i na kraju tova nisu utvrđene statistički značajne razlike između prosečnih masa ispitivanih grupa brojlera. Prosečan prirast za ceo period tova bio je najveći kod O-I grupe a najmanji kod K grupe brojlera, dok je ukupna konzumacija bila najveća kod K grupe a najmanja kod O-I grupe. Konverzija hrane bila je najbolja kod O-I grupe a najlošija kod kontrolne grupe brojlera. Prosečne mase trupova pre i posle hlađenja, zatim prosečne mase grudi i prosečne mase bataka sa karabatakom kao i njihova zastupljenost u masi trupa nisu se statistički značajno razlikovale između poređenih grupa brojlera. Takođe nije utvrđena statistički značajna razlika između prosečnih masa, odnosno učešća mesa u grudima, odnosno bataku sa karabatakom ispitivanih grupa brojlera. Između prosečnih pH vrednosti, odnosno prosečnih temperatura mesa merenih nakon 45 minuta, odnosno posle 24 sata od klanja nisu utvrđene statistički značajne razlike...The main objective of research under this doctoral thesis was to investigate the influence of conjugated linoleic acid (CLA) on performance (feed consumption, weight gain, conversion), the parameters of leanness (pocenat meat in the carcass) and meat quality of broilers (chemical composition, sensory characteristics, fatty acid composition including the content of CLA and content of malondialdehyde). For the experiment used broilers Cobb 500 provenience divided into four groups of 30 animals and fed standard diets as recommended by the manufacturer, provided that the groups differed only in the fact that the experimental group had a meal added to a commercial preparation of conjugated acid, the recommended amount of 2% in the mixture at different stages of production (O-I group 2% CLA since the beginning of the fattening period, O-II group 2% CLA of 11. days of fattening, O-III group 2% CLA of 22.days of fattening) and control (K group) without the addition of CLA. Mixtures were balanced and fully meet the needs of animals in all stages of this. At the end of fattening animals are weighed, calculated the amount of food consumed, and at the slaughterhouse sampled fat and meat for chemical analze (chemical composition of meat MDA and fatty acid composition) and sensory analysis. Samples of drumstick with thigh for determination of MDA were frozen at -18°C. At the slaughterhouse, the meat preservation after the measured weight of the basic parts (breast, drumstickwith thigh) carcass. In meal for broilers, balanced on the energy and protein content,were found statistically significant differences between average content of saturated, monounsaturated, polyunsaturated, n-3 and n-6 fatty acids. There was a statistically significant difference between the ratios of n-3 and n-6 fatty acids. Average total content of conjugated linoleic acid in the mixture for feeding experimental group of broilers was 4.43%. The feed of the control group was not detected conjugated linoleic acid. At the beginning of this, and then at the end of the first and second phases of fattening, as at the end of fattening there were no statistically significant differences between the average mass of examined groups of broilers. Average growth for the whole fattening period was highest in O-I group and the lowest in K group of broilers, while the total consumption was highest in K group and the lowest in O-I group. Feed conversion was the best in O-I group and the worst in the control group of chickens. Average carcass weight before and after cooling, then the average breast weight and the average weight of drumsticks with thighs as well as their representation in carcass weight did not significantly differ between the examined groups of broilers. There was also no statistically significant difference between the average weight and participation in breast meat and drumsticks with thighs examined groups of broilers. Between average pH value and the average temperature of meat measured after 45 minutes and after 24 hours of slaughter were no statistically significant differences..

Determination of weight loss and temperature of broiler carcasses during air cooling with intermittent water spraying: Case study

The aim of this study was to determine the broiler carcasses weight loss and temperature during air cooling with intermittent water spraying (3.1 m sec-1, -1.5°C, 120 min) in order to optimize the poultry chilling process. Weight and temperature of broiler carcasses were measured before and after cooling. Measurements were made once a week (during six weeks) on randomly selected broiler carcasses (eight carcasses per week) on the slaughterline. The most common broiler hybrids on the domestic market were used in the study (Ross-308, Cobb 500), of different ages (34 to 41 days old), which had been transported 70 to 260 km to the slaughterhouse. In broilers originating from flocks with higher average bird live body weight (2.2 to 2.4 kg), which were held longer (41 days), slight weight losses of carcasses occurred (0.32 to 0.76%) after cooling. On the other hand, broilers which were held 34-38 days with smaller average bird live weight (1.58 to 2.1 kg) produced slight increases in carcass weights after cooling (0 to 2.18%). Temperatures of the broiler carcasses before cooling ranged from 33.00 to 41.37°C and after cooling were from 1.58 to 5.46°C. The achieved temperature of broiler carcasses depended on carcass size, and was adequate (0 to 4°C) for broilers weighing less than 2.13 kg, but carcasses of larger birds did not meet temperature regulations. The transport length influenced weight loss of live broilers, but did not affect the weight loss of broiler carcasses after cooling. Also no differences were observed in accordance to the broiler hybrid type used (Ross-308, Cobb 500)

Toxoplasma gondii — control measures for reducing risks in the pork production chain

Parasites are highly significant pathogens that are transmitted through food. Their specific life cycles, transmission routes, and usually a lengthy period between infection and the first symptoms of the disease make them a substantial risk to public health. Additionally, there are challenges in detection, diagnosis, and treatment. Toxoplasmosis is considered the most widespread parasitic infection on a global scale. It is caused by the protozoan Toxoplasma gondii, one of the most successful parasites of animals and humans due to its ability to parasitize within the nuclei of a wide range of hosts. Because of its importance in both veterinary and human medicine, T. gondii is one of the most extensively studied parasites. Existing data show seroprevalences differ across continents, countries, and even within states and among specific communities. Consuming undercooked meat presents one of the greatest risk factors for human infection with the T. gondii parasite, with pork being recognized as a dominant source of infection

Toxoplasma gondii in pork and pigs in Serbia – a real food safety hazard

Infection with the apicomplexan protozoon Toxoplasma gondii is one of the most prevalent parasitic zoonotic infections globally, with existing seroprevalences varying between continents, countries, and even within countries and between individual communities. It is estimated that one third of the world's human population is infected with T. gondii, with many studies showing that the dominant mode of infection is consumption of undercooked meat harbouring T. gondii tissue cysts. Prevalences of infection in food animals in different countries range from 0 to 93%. Because of the absence of clinical symptoms in infected animals, and the unfeasibility of rapid and unequivocal detection of microscopic tissue cysts in pork, infected pigs remain unrecognized, and their meat becomes an essential source of infection for humans. The data on T. gondii infection in pigs in Serbia from several studies, as well as on the detection of the parasite in different food categories, from fresh pork to heat-treated products, are discussed

Određivanje Co-vrednosti kao pokazatelja hranljive vrednosti paštete sterilisane uobičajenim i optimizovanim postupkom

Introduction. Heat treatment of food provides appropriate shelf life and safety, as well as adequate sensory properties and better digestibility, but excessive thermal processing leads to the loss of nutritive value. In practice, sterilised meat products are usually overheated, which leads to a loss of nutritive value. Therefore, it is necessary to find the optimum between the preservative effect of heat treatment and maintenance of the nutritive value of food. Control of the sterilisation efficiency is based on the Fo value, an indicator of the lethal effect of heat treatment, while the cooking (Co) value indicates a reduction of the nutritive value of heat treated products. Materials and Methods. During pâté sterilisation processes, two working heat treatment regimes were used: the regime used in regular, commercial production and an optimised regime. Heat treatment measurements were carried out using six thermocouple probes placed in the geothermal centres of six chosen cans. For each heat treatment, schematic diagrams were produced. Fo values were determined using Ellab software, and Co values by the graphic method in a semi-logarithmic Thermal Death Time diagram. Results and Conclusions. During pâté sterilisation, where the effective time was 55 minutes (regular regime) at 114 °C and 3.2 bar pressure, an average Fo value of 7.90±0.43 was achieved. By reducing the effective sterilisation time to 45 minutes (optimised regime), an average Fo value of 3.81±0.5 was achieved. Both regimes were sufficient to ensure product safety (Fo >3). The average Co value for the regular sterilisation regime was 109.83±1.33 minutes, while for the optimised regime, it was 88.67±4.27 minutes, i.e., an average reduction of 19.26%. This corresponds to a proportionally higher nutritional value of the product treated using the optimised regime. Data on the Fo and Co values achieved during the sterilisation process can make a significant contribution to obtaining products with a better nutritional value through an optimised sterilisation process, without jeopardising product safety.Uvod. Toplotna obrda obzbeđuje održivost i bezbednost kao i adekvatna senzorna svojstva i bolju svarljivost hrane, ali suviše intenzivna topltona obrada dovodi do gubitka hranljive vrednosti. U redovnoj proizvodnji, sterilisani proizvodi od mesa se uobičajeno obrađuju suviše intenzivnim postupkom toplotne obrade, što dovodi do većeg dubitka hranljive vrednosti. Iz tog razloga, neophodno je da se pronađe optimum između konzervišućeg efekta toplotne obrade i očuvanja hranljive vrednosti hrane. Kontrola efkasnosti sterilizacije se bazira na određivanju Fo vrednsoti kao pokazatelja letalnog efekta toplotne obrade, dok Co vrednost (Cooking value) pokazuje smanjenje hranljive vrednosti toplotom obrađenih proizvoda. Materijal i metode. Za vreme sterilizacije paštete, primenjena su dva radna modela: postupak 'A' koji se koristi u redovnoj proizvodnji (uobičajeni režim) i postupak 'B' (optimizovani režim). Merenja su sprovedena pomoću 6 termopar sondi, koje su smeštene u geotermalnom centru 6 odabranih konzervi. Za svaki od toplotnih tretmana, iscrtani su dijagrami. Fo vrednost je određena Ellab softverom, a Co vrednost grafčkom metodom na polulogaritamskom TDT dijagramu. Rezultati i zaključak. Rezultati su pokazali da za vreme sterilizacije paštete, gde je efektivno vreme sterilizacije trajalo 55 min (uobičajeni režim), pri 114oC i pritisku od 3,2 bara, prosečna Fo vrednost iznosila 7,90 ± 0,43. Redukovanjem efektinog vremena sterilizacije na 45 minuta (optimizovani režim), postignuta je Fo vrednsot od 3,81 ± 0,5, pri čemu su oba režima bila dovoljna da osiguraju bezbednost proizvoda (Fo> 3). Co vrednost za uobičajeni režim sterilzacije je iznosila 109,83 ± 1,33 min, a za optimizovani režim 88.67 ± 4.27 min, pri čemu je ostvaren stepen redukcije od 19,26%, što odgovara proporcijonalno većoj hranljivoj vrednosti proizvoda tretiranog redukovanim režimom. Podaci o ostvarnim Fo i Co vrednostima za vreme postupka sterilizacije mogu da daju značajan doprinos u dobijanju proizvoda sa boljom hranljivom vrednosti kroz blaže postupke sterilizacije, a da se pri tome ne ugrozi bezbednost proizvoda

Problems in determining the nutrition declaration for unpacked meat products - example of domestic cooked sausage

This study aimed to determine the degree of change that unpacked pasteurized (i.e. cooked) sausages undergo during their shelf-life. For that purpose, unpacked domestic cooked sausages were examined for basic nutritional parameters, as are required to be stated on labels by local and EU legislation, at the beginning (day 1) and end of their shelf-life (day 40). Results showed the examined parameters varied significantly (the % variance range was 41.5-129.4%), which vastly exceeds the tolerance of variation limits allowed in the legislation (20-50%). The results obtained show the responsible authority would be unable to adequately control the nutrition declaration of these unpacked domestic cooked sausages. The inability to maintain the nutritional content according to the declaration of these unpacked meat products during their shelf-life is a great challenge for quality control of this type of meat product at retail

Relationships between broiler final weights and microbiota of certain segments of the intestine

Only healthy animals can expect good production results. Gastrointestinal tract (GIT) health is of particular importance in broilers. GIT health has been protected by antibiotics as growth promoters for years. Since their use is forbidden, alternatives are required. One alternative is the use of medium chain fatty acid (MCFA) in broiler nutrition, in order to ensure the health of digestive tract, that is, prevent the activity of pathogenic bacteria, coccidias and viruses. Today, commercial MCFA supplement is used on the market in nutrition of broilers and piglets. Previous experiences of using MCFA in nutrition of broilers suggest that MCFA can be used as a substitute for antibiotics. In the duodenum of experimental broilers (a group of birds fed with added MCFA), the numbers of Enterococcus spp. and E. coli were significantly correlated with bird weight, but this was not the case in other intestinal segments (ileum or caecum)

Prevalencija četiri gena virulentnosti u sojevima Campylobacter jejuni izoliranima iz mesa brojlera u Srbiji

Campylobacter jejuni is a major cause of human diarrheal disease. The objective of this research study was to determine the prevalence of different virulence genes in isolates recovered from broiler meat at slaughterhouses in Serbia. Out of 115 Campylobacter spp. samples recovered, a total of 35 isolates were identified as C. jejuni on the basis of morphological, biochemical-based detection, multiplex PCR, and sequencing of the highly conserved region of the dnaJ gene encoding the DnaJ Hsp40 family protein. The isolates were screened for the presence of four pathogenic genes, namely flaA, cadF, cdtB, and cgtB, which are responsible for the expression of adherence, colonization, cytotoxin production in C. jejuni, and the onset of Guillain-Barre syndrome. The isolates showed a wide variation in the presence of these genes. All the isolates were positive for flaA. Furthermore, a high genetic heterogeneity in the C. jejuni population was found in this study, showing a pattern partially different from other reported virulence genes. Of the C. jejuni studied, 94.3%, 97.1% and 5.7% were positive for cadF, cdtB and cgtB, respectively. This study provides initial data on the prevalence and distribution of the flaA, cadF, cdtB, and cgtB genes in C. jejuni isolated from broiler meat in Serbia.Campylobacter jejuni vodeći je uzročnik crijevnih bolesti koje se očituju proljevom kod ljudi. Cilj ovoga istraživanja bio je utvrditi prevalenciju različitih gena virulentnosti u izolatima dobivenima iz mesa brojlera u klaonicama u Srbiji. Na prisutnost vrsta roda Campylobacter spp. ukupno je pretraženo 115 uzoraka. Morfološko-biokemijskim pretragama, multipleks PCR tehnikom kao i sekvenciranjem visokoočuvane regije gena dnaJ, koji kodira sintezu proteina DnaJ iz obitelji proteina Hsp40, 35 izolata identificirano je kao C. jejuni. Izolati su pretraženi na prisutnost četiri gena patogenosti: flaA, cadF, cdtB i cgtB. Ti su geni odgovorni za ekspresiju adherencije, kolonizacije, sinteze citotoksina C. jejuni kao i nastanak Guillain-Barreova sindroma. Izolati su pokazali široku varijaciju u prisutnosti tih gena. Svi su izolati bili pozitivni na gen flaA, pri čemu je u populaciji C. jejuni iz ovoga istraživanja utvrđena visoka heterogenost u genetskoj strukturi, koja je djelomice različita od rezultata drugih autora. Kod 94,3 % izolata C. jejuni utvrđen je gen cadF, kod 97,1 % gen cdtB, a kod 5,7 % gen cgtB. Ovo istraživanje pruža početne podatke o prevalenciji i distribuciji gena flaA, cadF, cdtB i cgtB kod C. jejuni izoliranih iz mesa brojlera u klaonicama u Srbiji

Wooden breast - a novel myopathy recognized in broiler chickens

Abnormally hard breast fillet consistency began to emerge in commercial broiler chickens around 2010. Due to the remarkable muscle hardness, the condition acquired the vernacular name wooden breast myopathy. This myopathy starts to develop after two weeks of age at the earliest and typically proceeds into chronic myodegeneration in three to four weeks of age. The lesion begins focally and typically develops into a diffuse lesion that involves the entire major pectoral muscle. The restricted location of wooden breast lesion in the m. pectoralis major distinguishes it from several other myodegenerative diseases that widely affect the skeletal muscle system and often the cardiac and smooth muscle systems too. Although industry-wide incidence rates are difficult to assess, it has been estimated that approximately 5-10% of commercially produced breast fillets exhibit severe WB. Even at low incidence rates, the costs to industry are substantial, as breast fillets with the wooden breast condition are often downgraded and sold at a discount, used for further processing, or in extreme cases, discarded. Because the etiology of wooden breast is still unclear, in the future, study of the early lesions, pathogenesis and the possible reduction of animal welfare are likely to gain more attention

Optimization of pasteurization of meat products using pasteurization values (p-values)

This study aimed to examine the effect of shortening the effective heat treatment time by 15 minutes for finely and coarsely chopped sausages and canned meat in pieces packed in polyamide casings with diameters of 75 and 90 mm. Product safety was ensured in accordance with legislation and with the producer food safety system. Optimization led to a decrease in p-values for finely chopped sausages (diameter 90: 148.8 → 97.64 minutes; diameter 75: 111.2 → 58.4 min), coarsely chopped cooked sausages (diameter 90: 115.5 → 79.1 min; diameter 75: 245.3 → 106.6 min) and for canned meat in pieces (diameter 90: 249.7 → 95.91; diameter 75: 213.9 → 48.42 min). The use of p-value in optimization confirms the pasteurization level and ensures the safety of the product in the defined storage conditions. It is also possible to compare the levels of heat treatment for different products that are differently packaged