Browsing by Subject "Fleischqualität"

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Comparison of effects of Echinacea purpurea juices and Nigella sativa seeds on performance, some blood parameters, carcass and meat quality of broilers
(2009) Nasir, Zahid; Grashorn, Michael
Use of phytogenic substances in animal production is increasing due to their beneficial effects on feed digestion, promotion of production performance and improving product quality. They contain a number of pharmacologically active substances which have shown their activities in different body systems and, therefore, they are considered as one viable alternative to in-feed antibiotics. Presence of a variety of active ingredients indicates that phytogenic substances may have affects on different metabolic pathways, activity of different enzyme systems, immunity and performance parameters. Especially, improvement of immunity may help birds to cope in a better way with stress situations during fattening and by this may enhance well-being as well as quality of products of animal origin. Echinacea purpurea (EP) and Nigella sativa (NS) belong to the group of phytogenic substances that have been reported to stimulate immune system in laboratory trials as well as in human studies. Positive effects of EP and NS have been observed in a number of in vitro and in vivo experiments, which show that their application in poultry can be beneficial for maintaining health, improving immunity and performance parameters. However, no study was conducted to evaluate the comparative as well as synergistic effects of EP juices and NS seeds on broiler health, performance and activities of different enzymes related to heart and liver functions. The objectives of this thesis were set to investigate the effects of EP juices and grounded NS seeds on performance, metabolism (serum protein, blood picture and some liver and heart associated enzymes in blood), carcass and meat quality in broilers (Ross 308). For this purpose five preliminary trials were performed to investigate the effects on bird?s metabolism. Fattening trial was carried out to study the comparative and synergistic effects of EP juice and NS seeds on performance, carcass and meat quality. Three preliminary experiments were performed using two different preparations of EP juices; EP-F (EP fermented juice) and EP-A (EP juice on alcohol basis). Initially, effects of EP-F and EP-A were compared along with testing different dose levels. EP juices were orally supplemented intermittently for a 3 days (1-3, 13-15 and 25-27), followed by 9 days without EP application. Comparing the effects of EP-F and EP-A, better performance and improved health was observed by application of EP-F juices. Application of 0.25 ml/kg BW0.75 EP-F juice has shown more positive effects as compared to other treatment levels. EP-F treated birds showed significantly better average daily weight gain and significant improvement of serum globulins, indicating beneficial treatment effect on broiler performance as well as immunity. Levels of serum CK were significantly reduced in EP-F treated birds as compared to control, which shows that EP-F posses the potential to reduce incidence of mortality related to dysfunction of the cardio-vascular system in broilers. Two preliminary experiments were performed using grounded NS seeds. In first experiment different levels (0, 0.5, 1.0, 1.5, 2.0, and 2.5 %) of NS seeds were supplemented in basal broiler diets. 1 % NS was found to be most suitable, which was used in second experiment against a negative control. Numerically better FCR during starter phase was obtained by application of 1 % NS seeds, but these effects were decreased during grower phase. Less number of mortalities was observed in NS treated birds as compared to control. In the fattening trial, four treatment combinations were tested as: control (without any feed or water additive), E (drinking water intermittently supplemented with EP-F), N (feed supplemented with NS seeds) and EN (drinking water intermittently supplemented with EP-F and feed supplemented with NS). The results showed that application of EP-F as well as NS has no negative effect on broiler performance, carcass and meat quality. Birds performed to their maximum potential and supplementation of EP-F and NS helped birds to perform better. Combined application of EP and NS resulted in reduced mortality and numerical improvement in weight gain and feed consumption, significantly (P<0.05) higher meat CP as compared to E and N treatments. In general, a synergistic positive effect of simultaneous application of EP and NS was observed on performance, carcass and meat quality in broilers. Based on these results, it can be concluded that intermittent application of EP-F and continuous application of NS seeds has no negative effect on broiler performance, carcass and meat quality. Beneficial effects of Echinacea supplementation on broiler performance, health and immunity can be obtained by intermittent application of EP-F through drinking water. Combined application of EP-F and NS seeds has shown a trend of improved broiler performance and meat quality, which indicate synergistic effects of active ingredients of both phytogenic compounds.
Development of high quality niche products from local chicken and pig genetic resources
(2016) Muth, Philipp; Valle Zárate, Anne
This thesis indicates that the application of non-conventional and/or slow-growing pig and chicken genotypes alone does not guarantee a superior and/or distinctive meat color and quality of the products. It appears that the valorization of monogastric meat products through niche marketing is critically dependent on matching the respective genotype with appropriate production methods, thus, for instance, highlighting the need for producers to be discerning in regard to the choice of slaughter age and feeding strategy. In the case that these premises are implemented, a distinguished positioning of meat products derived from local pig and chicken genetic resources can be realized, and, expanded by standards that also take the social and economic dimensions of food value chains into account, translated into a common pool resource as a basis for an alternative food network. Efforts should then be directed toward the elaboration of stable distribution channels and effective governance structures in the respective food network.
Effects of immunological castration on the regulation of metabolism in boars
(2010) Bauer, Aneka; Claus, Rolf
Compared to surgical castrates, boars have a superior anabolic potential due to gonadal steroids, i.e. androgens and oestrogens. In consequence, they have an improved fattening performance and lean fat ratio in the carcass. However, most male piglets are surgically castrated without anaesthesia within the first week of life to avoid the unpleasant urine-like boar taint which is not acceptable to many consumers. Boar taint is mainly caused by androstenone which is synthesized in the testes together with the gonadal steroids. Skatole is another compound which contributes to the off odour. But this substance has a faecal smell and can be controlled by feeding strategies. Castration without anaesthesia is now regarded to cause acute pain and stress to the piglets, so that surgical castration is no longer tolerated due to animal welfare considerations. Different alternatives are discussed but it appears that active immunization against the gonadotropin releasing hormone (GnRH) is the most practicable alternative to surgical castration. It is based on application of a commercial antigen (Improvac®) two times at an interval of 4 weeks. The second vaccination then leads to a high antibody formation and to a blockade of GnRH and thus luteinizing hormone (LH). In turn, the testicular biosynthesis of anabolic hormones as well as androstenone is inhibited. Several studies found that immunized boars still had a better performance than surgical castrates. One explanation is that immunized boars maintain part of their anabolic potential before the second vaccination and thus the onset of antibody formation. Therefore, an exact time schedule for immunization is required to optimize the fattening period without risk of tainted carcasses at slaughter. Another explanation may be that high growth hormone (GH) concentrations are maintained in immunized boars at a boar specific level. In addition to low GH, barrows also have low concentrations of the anabolic insulin-like growth factor I (IGF-I). The present four studies were performed to investigate the hormonal and metabolic reactions before and after the second vaccination and to clarify why high GH concentrations are maintained. The cause for elevated GH levels in immunized boars could not be identified in the present studies. Nevertheless, results allow an exact timing of the vaccinations and thus an optimal use of the anabolic potential of immunized boars without the risk of tainted carcasses at slaughter. A further improvement of the fattening performance may be realized by feeding strategies and their influence on IGF-I.
Entwicklung, Implementierung und Bewertung eines IT-Systems zur Prozessdokumentation und -unterstützung in der landwirtschaftlichen Nutztierhaltung
(2010) Kuhlmann, Arne; Jungbluth, Thomas
In livestock farming, the use of automation technology is common. Automation technology is able to perform sub-processes, whereby the farmer is supported in his daily work. The data produced by this technology is usually monitored manually. The same applies to the collection of process parameters such as resource consumption and climate data. Therefore overall process monitoring and process documentation require high workload. Caused by structural change and the demand for food safety and traceability, livestock farming needs to introduce information technology. This document is dealing with the topics collection, storage, usage and exchange of data on farms and in their environment using the example of pig fattening. A stable for fattening pigs was used to analyse the conditions, requirements and implementation options for achieving the objectives process documentation and process support. Based on the conclusions drawn, a prototype was developed, that focuses on the full integration of all technical components in the stable using communication and data standards. Besides the presentation and evaluation of the system, concrete benefits for science and practice are presented using selected examples. Furthermore possibilities for improvements regarding the used technologies and standards are pointed out.
Physiologische und genetische Einflüsse auf die Qualität von Schweinefleisch aus baden-württembergischen Gebrauchskreuzungen
(2012) Fecke, Anna; Weiler, Ulrike
What genotypes, basing on the genetic lines supplied by German Genetic, guarantees both a high-value carcass and excellent pork quality and high eating quality and also how the criteria of fertility, weight development and yield at slaughter, relate to the criteria of pork quality. 10 genotypes were studied. Therefore the sows crossbred represent typically genotypes in Baden-Württemberg as well as the Leicoma hybrid sows. These sows were bred at the LSZ Boxberg with Pietrain and Duroc boars. The sows of the LW*(LC*DL) had the highest fertility rate. The boar lines showed no influence on either the birth weight or fertility parameters. The boar line, however, did reflect a highly significant influence on the daily gain in all further production periods (Duroc vs. Pietrain: suckling +8%; rearing +3,8%; fattening +6,5%).The offspring from the sows LW*(LC*DL) had the greatest daily gain in the suckling period and had a higher weaning weight (+6%, p<0.05) than the offspring from the LW*(SH*DL), which achieved the lowest overall weaning weight. On analyzing the relationship between the development weights in the various production periods and the birth weight, it was obvious that the birth weight provides a significant positive influence on the performance in every production period, except for rearing. Indeed, in the rearing period the animals with a high birth weight tended to show low daily gains, whereas the piglets with a low birth weight were able to partially compensate for the early growth deficit during this period. The Pietrain offspring had more lean meat content than the Duroc offspring. The dissection in Trial #2 shows that the Pietrain offspring had 3.3% more ham content and 4.0% more of the valuable cuts. The Duroc offspring had less lean meat content in the belly (-4.2%, Gruber Formula), more back fat (+13.7%), more leaf fat (+14.6%), and 12.5% more corrected fat area than the Pietrain offspring. The offspring of the sows LC*LW had a significantly shorter carcass than the offspring of the other sows. The offspring from the 50% Leicoma sows showed the greatest corrected fat area. The offspring from the sows LW*(LC*DL) had 17.1% less corrected fat area. The correlation analysis resulted in the established relationships. Especially of a practical interest, is the close relationship between lean meat content (FOM) and the pork underbelly (Gruber Formula) (r=0.92; n=240; p<0.001). For nearly every parameter the results of the pork quality grading under practical conditions (Trial #1) tended toward improved values for the pigs with Duroc genes, which showed a significantly lower drip loss. The influence of the sows on pork quality parameters was negligible. Besides these parameters, some carcasses were also characterized with PSE qualities (pH1<5.8; conductivity 24hr p.m.>8.0mS/cm). In Trial #1, based on the pH-readings at the slaughterhouse, almost no carcasses (0.15%) were identified with PSE, whereas the conductivity measurements in ham, 5.79% of the carcasses were identified as PSE. In Trial #2, 15.0% of the animals were PSE based on pH1 or conductivity measurements in the loin and ham. There were 5 carcasses which have PSE after both measurements in loin and ham. In the histochemical analysis of the muscle fiber classification the only difference between the boar lines was found in the percentage of red fibers. The eating quality tests revealed an influence from the boar line. In general, all genotypes produced a high quality lean meat content according to the market requirements. As to expectation the improved pork quality of the Duroc breed was justified by the best eating quality, an improved water-holding capacity and a higher intramuscular fat content. An acceptable overall pork quality can be achieved by pairing the offspring from the Pietrain*LW*(LC*DL). The offspring with some Schwäbisch-Hall genes have an opportunity to establish a regional market. However, their performance was not convincing because in fertility, in daily gain, and even in pork quality they attained below average values. Nevertheless, an optimal pork quality can be achieved more efficiently with other genotypes. On establishing predicting criteria, the percentage of PSE of the pork carcasses is quite positive. The superiority of the 24hr p.m. conductivity value for the drip loss predict is evident here. The measurement of the conductivity subsume the effects of slaughtering and cooling and is more appropriate than the pH1 value, especially, for the incoming inspection in the deboning area as well as for quality assurance.
Das Potenzial der teilmobilen Schlachtung von Rindern im Herkunftsbetrieb : Stressbelastung und Fleischqualität
(2022) Zeidler, Johannes
The industrialization of animal husbandry and the focus on large production volumes have led to the killing of farm animals taking place almost exclusively in what are now a few large slaughterhouses. Of the approximately 3.4 Mio cattle slaughtered in Germany in 2019, nearly 78% are slaughtered in Germanys 10 largest slaughterhouses. Local butchers and small slaughterhouses often cannot comply with the strict legal hygiene regulations. The animals must therefore be transported alive, where loading, the journey, the foreign environment, the separation from the herd and the meeting with unfamiliar animals and humans, are known to cause stress and as well have negative impacts on meat quality. Since the revision of the EU regulation 853/2004 in 2021, slaughter at the farm of origin is now considered an official slaughter method. Although research focussing on slaughtering cattle on the farm of origin using captive bold stunning is missing, meat of cattle slaughtered via gunshot on pasture tends to be more tender and stress levels can be reduced in comparison to cattle slaughtered in the slaughterhouse. This leads to the assumption that also slaughtering cattle on the farm of origin, using captive bolt stunning, should result in higher meat quality and reduce stress prior to slaughter. For this purpose, this study examined 27 cattle from seven different farms slaughtered either on farm of origin using captive bolt stunning, via gunshot or in commercial slaughterhouses. Meat quality parameters and stress indicators were assessed to evaluate these three slaughter methods from a meat quality and an animal welfare perspective Based on the cortisol levels in the blood of exsanguination, no significant differences in the stress levels of the different slaughter methods could be determined. Nevertheless, tendencies towards less stressed animals with slaughtered via gunshot and slaughtered on the farm of origin using captive bolt stunning compared to the slaughterhouse could be revealed. As large variances of cortisol concentrations were measured within cattle slaughtered on farm of origin, stress level seems to depend on the individual slaughtering and preparing procedure. Further research is needed to improve and give recommendations for practical implementation of this method taking different farm structures into account. Quality parameters were not unambiguous. A significant effect of the slaughter method could only be found on ultimate pH-value and redness (a* L*a*b* System). Contrary to our expectations, ultimate pH-value was significantly lower in meat of cattle slaughtered on farm of origin using captive bolt stunning than in meat of cattle slaughtered via gunshot. Moreover, cattle slaughtered on farm of origin using captive bold, had significantly redder meat than cattle slaughtered via gunshot This contradicts the assumption that more stress leads to less red meat. However, it is consistent with the lower pH values of meat from cattle slaughtered with bolt stunning at the farm of origin, because low pH values lead to redder meat. Exploratory results comparing only meat from commercial slaughterhouses with meat from cattle slaughtered on farm using captive bolt stunning show clearer trends. Lower ultimate pH-values, as well as trends towards more tender and juicy meat could be found in cattle slaughtered on farm. To ensure these results and to evaluate meat quality according to different slaughter methods in upcoming research, either environmental effects should be reduced, or the dataset must be larger.
Process, structure and function relationship in ground meat
(2023) Berger, Lisa Marie; Weiss, Jochen
Ground beef has enjoyed high popularity with consumers because it is convenient to use and facilitates a rapid preparation of a large variety of different meals. In the production of ground meat, the particle size of the meat is systematically reduced, and the cell structures are partially disintegrated. Ideally, the original cellular meat or fat structure is preserved as much as possible so that important quality attributes are optimized. However, the effect of varying conditions and parameters in modern processes on the quality of ground meat has not yet been investigated in detail. According to the current German “Leitsätze für Fleisch und Fleischerzeugnisse”, hamburgers must not contain more than 20 Vol.% of non-intact cell structures to be sold without further declaration. Therefore, this work aimed to identify process, structure, and function relationships in ground meat production to facilitate a gentler processing of in particular hamburgers. To investigate these effects systematically, a standardized production method for hamburgers was developed and a pilot plant scale meat grinder was set up with the possibility to record process-relevant data. The relationship between the structure and functionality of ground meat was investigated using a model system with increasing amounts of added meat batter to simulate changes in meat structure due to cell disintegration. A new term, i.e., the amount of non-intact cells (ANIC), was introduced to quantify the amount of disintegrated meat cells during processing. It was shown that changes in the structure due to a higher or lower ANIC resulted in altered physicochemical and functional properties of the ground meat system. The effect of frozen meat content and temperature on the structure and function of hamburgers was investigated to verify the above-obtained correlation to an application-relevant setting. As the specific cutting resistance is significantly higher in frozen than in chilled meat, it was assumed, that the impact on the ground meat’s structure and function differed accordingly. Indeed, this could be verified. In hamburger manufacturing, it is common practice to re-fed imperfectly molded patties, e.g., in a frozen, coarsely crushed state. In contrast to those findings, the use of up to 20 % re-fed material in hamburger manufacturing did not result in any noticeable differences as neither the specific mechanical energy input (SME) nor the ANIC was significantly changed. It was thus demonstrated, that some raw material variations can have an impact on both structure and function of hamburgers. Especially, temperature effects and associated changes in the cutting resistance of the raw material had the strongest influence on structure and function of ground meat. However, if structural differences were found, they were not sufficient to manifest in differences in sensory evaluation. This means that the consumer perception and thus the quality of the hamburger was not influenced. The process parameters and their impact on the structure and function of hamburgers were studied by investigating the impact of the four main processing steps pre-grinding, mixing, grinding, and forming. An increased ANIC was determined with progressive processing, whereby the grinding steps accounted for the strongest increase. Mixing and forming were of minor importance for structural and functional changes. By varying the cutting set parameters, the influence of the cutting set compositions on the structure and function of hamburgers was assessed. The SME and the ANIC increased if more cutting levels were used due to higher shear stress applied to the meat. However, the hole plate properties did cause no or only negligible changes in the ANIC and SME. Although an impact of the cutting set composition on the structure could be found, no or only marginal effects on the function and the sensory and optical quality of the hamburgers were found. It can therefore be concluded that the shear forces acting on the meat during grinding have the strongest influence on the structure and function of beef. By reducing the acting shear forces, the grinding can be designed to be gentler resulting in lower ANIC. Despite the influence on the process-control (SME, pressure, torque) and the structural parameters (ANIC), it needs to be emphasized that the influence on the function and quality of the hamburgers is small in application-relevant ranges. In application-relevant ranges this relationship is only slightly pronounced. Comparable results were found, as raw material variations only partially caused structural, functional, and quality effects in the hamburgers. This in turn means that changes in structure cannot always be linked to a shift in perceived quality. In order to carry out an integrated evaluation of the product, structural parameters and quality parameters must be defined, assessed separately, and merged into a combined overall sample assessment.
Versuche zur Verbesserung der sensorischen Fleischqualität beim Schwein durch nutritive Hemmung der Skatolbildung
(2006) Lösel, Dorothea; Claus, Rolf
Skatole is known to occur in pork carcasses. Due to its pronounced faecal odour, it may have an adverse effect on sensorial quality of pork. Skatole has been associated with boar taint, but is also formed in the large intestine of barrows and gilts by bacterial degradation of tryptophan. As apoptotic cells from the gut mucosa are the main source of tryptophan, skatole formation is partly linked to the degree of cell renewal in the gut. A part of microbially formed skatole is absorbed and stored in adipose tissue due to its lipophilic properties. In earlier studies it has been shown that intestinal butyrate formation increased by feeding resistant potato starch. This short-chain fatty acid reduced the apoptotic activity in the gut mucosa and thus decreased skatole formation and tissue accumulation. Therefore, it was the aim of the present study to investigate whether this method is applicable to improve sensorial quality of pork under routine fattening conditions. In the first experiment the amount of potato starch required for sufficient reduction of skatole was determined. Four groups of pigs received diets containing different amounts of potato starch (0 % as a control, 20 %, 30 %, 40 %) for 2-3 weeks prior to slaughter. Skatole concentrations in gut content (proximal and distal colon, rectum) and adipose tissue (flare fat and ventral fat) were determined by High Performace Liquid Chromatography. An amount of 30 % in the diet reduced skatole concentrations in gut content and adipose tissue compared to the control. The reduction was 98 % in the proximal colon, 93 % in the distal colon and 89 % in the rectum. Skatole concentrations in flare fat decreased by 84 %. Feeding a higher amount of potato starch (40 %) did not result in a significant further reduction. Therefore, in the following experiment (consisting of two replicates) diets of treatment groups contained 30 % of potato starch. In each replicate, 80 Baden-Württemberg Hybrids (barrows and gilts) were fed the diets during the whole fattening period. The control groups received a conventional diet based on grain and soya and a diet with a proportion of 30 % gelatinized starch in replicate 1 and 2, respectively. Skatole concentrations were determined in gut content (proximal and distal colon, rectum), blood plasma and adipose tissue (flare fat, ventral fat and back fat). Apoptosis in the colonic mucosa was determined cytochemically. From each replicate cutlets from 12 control pigs and 12 potato starch pigs were used for sensorial evaluation. The panellists evaluated samples for aroma of meat juice, and aroma and taste of meat according to a 5-point scale. The attributes were from 1 (very unpleasant) to 5 (very pleasant). A trend towards reduced apoptosis was demonstrated in the upper crypt compartment in the proximal colon. Intestinal skatole formation decreased from 50-60 µg/g dry matter to values around the lower limit of detection (0.4 µg/g). Thus, less skatole was absorbed and the mean concentrations in blood plasma were reduced by 45-65 %. In adipose tissue, concentrations in the potato starch group decreased by 57-90 % compared to the controls. Therefore, the variation of concentrations was reduced, so that 90 % of the potato starch pigs had values below 20 ng/g. Concentrations in gut content, blood plasma and adipose tissue were significantly correlated. In replicate 1, sensorial evaluation showed that cutlets containing between 0 and 2.78 ng/g skatole in fat had better ratings for aroma of meat juice and meat than samples with mean (up to 28 ng/g) or high (up to 78 ng/g) skatole concentrations. Also, the overall impression was significantly improved. In replicate 2, there was still a tendency to these differences. In conclusion, this study shows that the reduction of intestinal skatole formation by feeding resistant starch can improve the aroma of pork. For routine application, it would be sufficient to feed the potato starch diet for only a few days prior to slaughter.