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Darbo tikslas: ištirti ksilanazių, beta gliukanazių, celiulazių ir amonio propionato bei pieno rūgšties įtaką viščiukų broilerių virškinimo procesams. Uždaviniai: 1. ištirti ksilanazių, beta gliukanazių, celiulazių ir amonio propionato bei pieno rūgšties įtaką viščiukų broilerių produktyvumui. 2. ištirti ksilanazių, beta gliukanazių, celiulazių ir amonio propionato bei pieno rūgšties įtaką viščiukų broilerių virškinimo procesams. Išvados: 1. Fermentinio preparato (pagrindiniai fermentiniai aktyvumai - ksilanazių, beta gliukanazių, celiulazių) tiek vieno, tiek kartu su organinėmis rūgštimis (amonio propionato pieno rūgštis) įtakojo viščiukų broilerių kūno masės didėjimą 2 proc., lesalų sąnaudų 1 kg priesvorio gauti sumažėjimą 6 proc., lyginant su kontroline grupe (p > 0,05). Lesalų priedai neturėjo įtakos viščiukų broilerių gaištamumui. 2. Fermentinio preparato ir organinių rūgščių poveikyje pH turėjo didėjimo tendencija dvylikapirštės ir plonosios žarnų, turinyje tuo tarpu aklosios žarnos turinyje šis rodiklis buvo žemesnis, lyginant su kontroline grupe (p > 0,05). 3. Lesalų priedų panaudojimas, įtakojo didesni SM kiekį viščiukų broilerių virškinamojo trakto turinyje, lyginant su kontroline grupe. 4. Fermentinio preparato poveikyje (II tiriamoji grupė) acto, propiono ir sviesto rūgščių kiekis aklosios žarnos turinyje padidėjo nežymiai, atitinkamai 0,1, 0,12 ir 0,08 proc., o III tiriamojoje grupėje (fermentinis preparatas + organinės rūgštys) acto ir sviesto rūgščių kiekis... [toliau žr. visą tekstą] / The aim of the work: to investigate the influence of xylanase, beta glucanase, cellulase, ammonium propionate and lactic acid on digestion process of broiler chickens. The tasks of labor: 1. to investigate the influence of of xylanase, beta glucanase, cellulase, ammonium propionate and lactic acid on productivity of broiler chickens; 2. to investigate the influence of xylanase, beta glucanase, cellulase, ammonium propionate and lactic acid on digestion process of broiler chickens. Conclusious: 1. Enzymes (xylanase, beta glucanase, cellulase) used alone or with organic acids (ammonium propionate, lactic acid) influenced the weight increase of broiler chickens by 2%, feed consumption per 1kg decrease in weight gain was 6%, compared with the control group (p > 0.05). Feed additives had no effect on mortality of broiler chickens. 2. pH tends to increase in the duodenum and small intestine, while in caecum this rate was lower compared to the control group (p > 0.05). 3. The use of feed additives influenced the higher DM content in broiler chickens digestive tract content, compared with the control group. 4. In the second experimental group acetic, propionic and butyric acids increased slightly, by 0.1, 0.12 and 0.08%, compared to the control group (p > 0.05). In the third experimental group acetic and propionic acids increased by 0.93 and 0.33%, while butyric acids decreased by 0.65% compared with the control group (p > 0.05). 5. In both - the second and the third – investigated... [to full text]

Darbo tikslas: ištirti kvietrugių maistinę vertę ir jų panaudojimo galimybes viščiukų broilerių mityboje. Darbo uždaviniai: ištirti kvietrugių maistinę vertę; ištirti kvietrugių įtaką viščiukų broilerių virškinimo procesams. Rezultatai: išanalizavus 11 kvietrugių veislių nustatytas vidutinis žalių baltymų kiekis – 11,99 proc., žalių riebalų – 0,83 proc., žalių pelenų – 1,31 proc., vidutinis krakmolo kiekis – 69,69 proc., kalcio – 0,07 proc., fosforo – 0,303 proc. Pagrindinių aminorūgščių, lizino, metionino, treonino ir triptofano vidutiniai kiekiai atitinkamai nustatyti – 0,36 proc., 0,17 proc., 0,3 proc., 0,13 proc. Naudojant viščiukų lesinimui multifunkcinį fermentą bei kvietrugių veislę Tulus žarnyno svoris, ilgis bei aklosios žarnos ilgis mažėjo 4 – 6 proc., o naudojant veislę Lego - esminių pokyčių nenustatyta. Naudojant fermentą bei kvietrugių veisles Lego ir Tulus širdies svoris padidėjo atitinkamai 8 ir 10 proc., lesinant minėtas kvietrugių veisles ir fermentą kepenų svoris padidėjo atitinkamai 10 ir 8 proc. Naudojant viščiukų lesinimui multifunkcinį fermentinį priedą virškinamosios masės klampumas viščiukų broilerių aklojoje žarnoje padidėjo 11 – 23 proc. / Purpose of work: investigate the nutritional value of triticale as well as the use of it as a feed to broiler chicken. The tasks of work: investigation of triticale nutritional value; investigation of triticale influence to digestive processes of broiler chicken. Results: an analysis of 11 triticale varieties has shown that the average crude protein content is 11.99 percent, crude fat 0.83 percent, green ash 1.31 percent, starch 69.69 percent, calcium - 0.07 percent, phosphorus - 0.303 percent. The average amount of basic amino acids, lysine, methionine and tryptophan in triticale are as follows: 0.36 percent, 0.17 percent, 0.3 percent, 0.13 percent. The research has shown that by using multifunctional enzymes and triticale variety Tulus intestinal weight, length and caecum length decreased by 4-6 percent; whereas the use of triticale variety Lego has resulted in no major differences. The use of both varieties Lego and Tulus resulted in increase of heart weight by 8-10 percent and increase in liver weight by 10 for Lego and 8 percent for Tulus variety. The use of multifunctional enzyme has also resulted in viscosity of digestible mass in an increase in broiler caecum by 11-23 percent.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Small-scale farmers have the opportunity to gain access to markets through a contract farming arrangement. The key question is whether it is financially feasible for a small-scale farmer to enter into a contract. The objectives of this study were to develop a model that could be used to determine the financial feasibility of small-scale contract broiler farming in an intensive production system, compare three different genotypes namely: Cobb500 males X Hybro G females, Ross 308 males X Potchefstroom Koekoek females (crossbred) and the purebred Potchefstroom Koekoek, and evaluate current smallscale farmers’ broiler production by means of a case study. Financial performance indicators such as the net present value, cash flow and profit and loss statements were used to analyze the feasibility of all the scenarios. The model was built in Microsoft Excel. Five hundred, 1500 and 2500 birds/cycle scale of production were analyzed. Results revealed that based on the capital costs used, a 500 birds/cycle scale of production was uneconomical and that a farmer would have to receive R25.01/kg broiler meat in order to break even. The 1500 scale of production showed much better results. A farmer could break even at R17.51/kg meat. The capital investment cost of the 2500 scale of production was so high that the farmer would have had to sell his broiler meat for R18.54/kg. Performance traits of genotypes were collected through an experiment and data was statistically analyzed using ‘Statistica 9’. Results showed that there were significant differences between the cumulative feed intake, feed conversion ratios and the European production efficiency ratio of the different genotypes. No significant difference was found in the liveability of the genotypes. Data on performance traits was used as input into the model so that the economic feasibility of the genotypes could be compared. Results showed that a purebred Potchefstroom Koekoek genotype was not suitable for an intensive production system and that the crossbreed did not perform as well as the broiler breed, but that it would be worthwhile investigating the performance traits of the cross breed under less optimal conditions or in a free-range system. The lower capital costs necessary for a freerange system, together with the high premium paid for free-range broiler meat, may give admirable results in the economic feasibility of a small-scale broiler farm. / AFRIKAANSE OPSOMMING: Kleinboere het die geleentheid om deur kontrak boerdery toegang tot markte te verkry. Die vraag is egter of dit finansieël haalbaar is vir 'n kleinboer om kontraktueel verbind te word? Die doelwitte van die studie was om: ‘n model te ontwikkel wat gebruik kan word om die finansiële lewensvatbaarheid van' n klein-skaalse braaikuikenboer te bepaal onder 'n intensiewe produksiestelsel; verskillende genotipes naamlik: Cobb500 hane X Hybro G henne, Ross 308 hane X Potchefstroom Koekoek henne (kruising) en die suiwer Potchefstroom Koekoek te evalueer en die die huidige klein-skaal boer se braaikuikenproduksie deur middel van 'n gevallestudie te evalueer. Finansiële prestasie aanwysers soos die netto huidige waarde, kontantvloei, asook wins en verlies state was gebruik om die haalbaarheid van die verskeie gevalle te analiseer. Die model is op Microsoft Excel gebou. ‘n Produksie skaal van 500, 1500 en 2500 kuikens/siklus is ontleed. Resultate het getoon dat, gebaseer op die kapitale koste wat gebruik is, 'n produksie skaal van 500 kuikens/siklus onekonomies is en dat ʼn boer R25.01/kg sal moet ontvang om gelyk te breek. Die produksie skaal van 1500 kuikens/siklus het beter resultate getoon. 'n Boer kan gelyk breek teen R17.51/kg vleis. Die kapitale beleggingskoste van die produksie skaal van 2500 kuikens/siklus was so hoog dat die boer R18.54/kg sou moes ontvang het om gelyk te breek. Prestasie van genotipes is ingesamel deur middel van 'n eksperiment en data is statisties ontleed met behulp van Statistica 9. Resultate het getoon dat daar hoogs beduidende verskille tussen die kumulatiewe voerinname, voeromsetsverhoudings en Europese produksie effektiwiteits verhouding van die verskillende genotipes is. Geen beduidende verskil is gevind in die leefbaarheid van die genotipes nie. Inligting oor die prestasie eienskappe is gebruik as insette tot die model sodat die ekonomiese haalbaarheid van die genotipes vergelyk kon word. Resultate het getoon dat 'n suiwer Potchefstroom Koekoek genotipe nie geskik is vir 'n intensiewe produksie stelsel nie en dat die kruising nie so goed soos die braaikuiken gevaar het nie, maar dat dit die moeite werd sal wees om ondersoek in te stel na die produksie potensiaal van die kruis kuiken in minder optimale toestande, soos ‘n vryloop stelsel. Die laer kapitale koste en die hoë premie wat betaal word vir vryloop braaikuikenvleis mag geloofwaardige resultate op die ekonomiese haalbaarheid van 'n kleinskaalse braaikuikenboer toon.

Resumo: Foram avaliados parâmetros fisiológicos e imunológicos de matrizes de corte vacinadas ou não contra o vírus da bronquite infecciosa das galinhas (VBIG), submetidas a diferentes períodos de jejum após a eclosão, seguido de alimentação até a terceira semana de vida. No Capítulo 2, encontram-se os resultados do desempenho zootécnico e o desenvolvimento de órgãos gastrintestinais. No Capítulo 3, estão descritos os resultados de parâmetros hematológicos e bioquímicos. O Capítulo 4 apresenta as cinéticas de decaimento dos anticorpos maternos e os perfis cinéticos da reposta imune humoral nos compartimentos local e sistêmico. A vacina contra a BIG influenciou parâmetros de desempenho, de morfometria intestinal, o hematócrito, parâmetros bioquímicos, percentuais de heterófilos e linfócitos e induziu a resposta imune humoral na secreção lacrimal. O jejum pós-eclosão prolongado seguido de alimentação influenciou negativamente o desempenho, o desenvolvimento das vísceras gastrintestinais, as variáveis bioquímicas, imunológicas e a maioria das variáveis hematológicas. Os dados indicam que períodos de jejum pós-eclosão superiores a 48 h devem ser evitados, pois ao afetar negativamente parâmetros hematológicos, intestinais e imunológicos, podem comprometer o crescimento das matrizes e inferir negativamente sobre sua resposta imune. No entanto, o jejum moderado pode favorecer a resposta imune vacinal / Abstract: Immunological and physiological parameters were evaluated in broiler breeder vaccinated or not against infectious bronchitis virus (IBV), submitted to different periods of fasting post-hatching, followed by feed until the third week of life. In Chapter 2, are the results of zootechnical performance and development of gastrointestinal organs. The Chapter 3 describes the results of hematological and biochemical parameters of blood. Chapter 4 presents the kinetics of decay of maternal antibodies and the kinetic profiles of humoral immune response in local and systemic compartments. The IBV vaccine influenced parameters of performance, intestinal morphology, hematocrit, biochemical parameters, percentage of heterophils and lymphocytes, and induced humoral immune response in tear secretion. Prolonged fasting post-hatching, followed by feeding, negatively affected the performance, the development of gastrointestinal organs, biochemical variables, immunological and the most of hematological variables. The data indicate that periods of fasting post-hatching over 48 h should be avoided as they adversely affect the hematological, gastrointestinal and immunologic, may compromise the growth of broiler breeder and infer a negative effect on their immune response. However, moderate fasting can promote the immune response vaccine / Orientador: Renato Luís Furlan / Coorientador: Hélio José Montassier / Banca: Ricardo de Albuquerque / Banca: Vera Maria Barbosa de Moraes / Mestre

Resumo: O estresse por calor é considerado um dos fatores de maior impacto na criação de frangos de corte, já que exerce grande influência no desempenho e na qualidade da carcaça, bem como no perfil de expressão de genes relacionados ao crescimento e desenvolvimento animal. Assim, o presente trabalho objetivou verificar o efeito da temperatura e da restrição alimentar no desempenho, composição de carcaça e nos padrões de expressão de genes envolvidos na regulação do crescimento e desenvolvimento (GHR, IGF-I e IGF-IR), aos 21 e 42 dias de idade dos frangos de corte pela técnica de PCR quantitativo em tempo real. Os resultados evidenciaram que a restrição alimentar imposta pela exposição ao calor reduziu o desempenho e rendimento de peito e aumentou o rendimento de coxas+sobrecoxas. O estresse por calor e o consumo de ração alteraram o rendimento de asas, mas não influenciaram o rendimento de carcaça e de gordura abdominal. O calor aumentou o teor de extrato etéreo no peito e nas asas e diminuiu o de matéria mineral nas coxas+sobrecoxas. Independente da temperatura de criação, a restrição alimentar exerce um efeito negativo na expressão do gene do GHR no fígado das aves jovens, sem maiores reflexos na expressão do gene do IGF-I. O estresse térmico afeta a expressão dos genes hepáticos GHR e IGF-I somente nas aves adultas, as quais apresentam perfil inverso ao das aves restritas pelo "pair-feeding". A reação de amplificação do gene IGF-IR apresentou formação de produtos de amplificação inespecíficos, assim como formação de estruturas secundárias das moléculas dos iniciadores (dímeros e "hairpins"), o que impossibilitou a análise dos resultados / Abstract: Heat stress is considered one of greatest impact factors on broiler chicken production, once that it has great influence on the performance and carcass quality, as well as on the expression profile of genes related to growth and animal development. Thus, the present work had the objective of verifying the effect of temperature and food restriction on the performance, carcass composition and expression pattern of genes involved in the growth regulation and development (GHR, IGF-I and IGF-IR), at 21 and 42 days of age of the broilers using the PCR quantitative real-time technique. The results showed that the food restriction imposed by heat exposure, affected negatively the performance and breast yield and, positively, the tight and drumstick yield. The heat stress and feed intake altered the yield of wings, but did not affect carcass yield and abdominal fat. The heat increased both ether extract content in the breast and wings and reduced the mineral matter content in the tights and drumsticks. Independent of temperature, in the young bird's livers, food restriction endorses a negative effect on the GHR gene expression, without greatest reflects on IGF-I expression. Only on adult bird's, thermal stress affects the expression of GHR and IGF-I hepatic genes, that exhibit an inverse profile of restricted pair-feeding birds. The amplification reaction of IGF-IR gene showed both formation of nonspecific amplification products, as well as secondary structures of the primers of the molecules (dimerous and hairpins), precluding the analysis of results / Orientador: Renato Luís Furlan / Coorientador: Luiz Roberto Furlan / Banca: João Martins Pizauro Júnior / Banca: Poliana Fernanda Giachetto / Mestre

Orientador: Elisa Helena Giglio Ponsano / coorientador: Manoel Garcia Neto / Banca: Paulo César Ciarlini / Banca: Elizabeth Santin / Resumo: O subproduto de acerola é uma rica fonte de compostos bioativos que apresentam alta atividade antioxidante. No presente estudo, o desempenho produtivo, a população microbiana cecal, as características da carne, os parâmetros bioquímicos e a atividade antioxidante e oxidante sérica de frangos de corte alimentados com ração adicionada de farelo de subproduto de acerola (FAC), como um ingrediente alternativo, foram comparados com os mesmos parâmetros de frangos de corte alimentandos sem adição de FAC mas com agente melhorador de desempenho (AMD) e antioxidante sintético (AS). As dietas experimentais foram: controle positivo (CP), contendo 0,007% de sulfato de colistina 8% (AMD) e 0,01% de butilhidroxitolueno (BHT) (AS), controle negativo (CN), sem AMD, AS ou FAC, dieta com 5% de FAC (AC 5%) e dieta com 7,5% de FAC (AC 7,5%). Cento e sessenta pintinhos (Cobb 500) foram vacinados com a vacina Livacox T, via ocular e distribuídos aleatoriamente em 16 boxes, com 4 repetições por tratamento, contendo 10 aves em cada. Os animais foram. Parâmetros produtivos foram mensurados semanalmente até 42 dias de idade, quando os animais foram abatidos e a carne, o sangue e o conteúdo cecal foram coletados para as análises de cor/rancidez oxidativa, a contagem da população bacteriana cecal, os parâmetros bioquímicos e o status oxidante/antioxidante sérico. Não houve diferenças para ganho de peso, consumo de ração e conversão alimentar entre os diferentes grupos, assim como para os rendimentos de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Acerola byproducts are a rich source of bioactive compounds with high antioxidant activity. In the present study, productive performance, bacterial caecal population, meat characteristics, biochemical parameters and serum antioxidant status of broilers fed acerola byproduct (ACM) as an alternative ingredient were compared with the same parameters of broilers fed diets with no ACM but with antimicrobial growth promoters (AGP) and synthetic antioxidant (SA). The experimental diets comprised: positive control (PC), containing 0.007% colistin sulfate 8% (AGP) and 0.01% butylated hydroxytoluene (BHT) (SA) and no ACM; negative control (NC), without AGP, AS or ACM; diet with 5% ACM (AC 5%); and diet with 7.5% ACM (AC 7.5%). One hundred sixty one day old Cobb 500 male chicks were vaccinated with Livacox T via ocular and randomly distributed into 16 pens. Four repetitions were performed, with ten birds per pen. used in the experiment. Productive parameters were measured weekly until day 42, when the broilers were slaughtered and the meat, the blood and the caecal contents were collected for the analyses of oxidative rancidity and color of the meat, serum oxidant/antioxidant status and caecal bacterial population counts. There were no differences among the treatments regarding to feed intake, body weight gain and feed conversion, as well as to dressing percent and live weight. Only ACM at 5% caused an increase in the caecal lactic bacteria count. Breast color and thigh lipid rancicity ... (Complete abstract click electronic access below) / Mestre

Orientador: Hirasilva Borba Alves de Souza / Banca: Alexandre Oba / Banca: Vera Maria Barbosa de Moraes / Resumo: Esse experimento objetivou avaliar o desempenho, rendimento de carcaça e características qualitativas da carne do peito de frangos de corte alimentados com dietas suplementadas com diferentes concentrações (0,3 e 0,5 mg/kg de ração) e fontes (orgânica e inorgânica) de Selênio, sendo o Sel-Plex TM e o selenito de sódio as fontes utilizadas. Utilizou-se 1050 aves (machos), que receberam rações isoproteicas e isoenergéticas em todas as fases de criação (1 a 21, 22 a 35 e 36 a 42 dias). Foi utilizado o esquema fatorial 2X2 + 1 (2 concentrações X 2 fontes de Se + controle) em delineamento inteiramente casualizado, com 5 tratamentos e 7 repetições, com 30 aves por parcela. A viabilidade foi melhorada com a suplementação da ração com Selênio, independente da fonte utilizada. No período de 1 a 21 dias, a suplementação melhorou o desempenho das aves, através de menor conversão alimentar.Porém, nos períodos de 1 a 35 e 1 a 42 dias o consumo de ração e o ganho de peso pioraram com a suplementação. Das fontes utilizadas, a orgânica promoveu melhora significativa no desempenho das aves em todos os períodos, sendo que os melhores resultados foram obtidos com a concentração de 0,5 mg de Se/kg de ração. Nenhum dos fatores influenciou o rendimento de carcaça e cortes. A utilização da fonte orgânica ao invés da inorgânica diminuiu a taxa de oxidação da carne do peito das aves armazenada por 7 e 15 dias a 4ºC, além de ocasionar menor luminosidade e maior pH. Houve influência das fontes e das concentrações sobre a deposição de selênio na carne, sendo a fonte orgânica superior à inorgânica e o nível de 0,5 superior ao de 0,3 mg de Se/kg de ração. A concentração de 0,5 mg de Se/kg de ração na dieta proporcionou aumento da porcentagem de cinzas na carne. / Abstract: This study was conducted to evaluate the effect of different concentrations (0,3 and 0,5 mg/kg) and sources (organic and inorganic) of selenium on performance, carcass and parts yield and breast meat quality of broilers (Cobb 500). 1050 one-day-old male chicks were distributed in a completely randomized design in a 2x2+1 factorial arrangement (2 concentrations, 2 sources and 1 control diet), with 7 repetitions per treatment and 30 birds per replicate. The experiment lasted 42 days and the diet for each phase (1-21, 1-35 and 1-42 days) were corn-soybean meal based. The results showed better viability when the supplemented diets were used, independent of the source. In the first period (1 to 21 days), the supplementation provided an improvement on performance, with better feed conversion. However, the results were different in the others breeding phases (1 - 35 and 1 - 42 days), with decrease (P<0,05) on feed intake and weight gain when the supplementation was used. The organic source (Sel-Plex®) provided better results when offered in the second concentration (0,5 mg/kg). None of the factors influenced the carcass and parts yields. The organic source provided a significant decrease in the meat oxidation when it was stored for 7 and 15 days (4ºC). The lightness tended to decrease and the pH tended to increase when the Se-enriched-yeast (Sel-Plex®) was used. There were source and concentration effects on the meat selenium deposition, being the organic source better than the inorganic source (sodium selenite) and the second concentration (0,5 mg/kg) better than the first (0,3 mg/kg).The concentration of 0,5 mg/kg provided increase of the percentage of ashes in the meat. / Mestre

Die vorliegende Untersuchung diente, nach der grundlegenden Vorgehensweise im Rahmen des exponentiellen N-Verwertungsmodelles (GEBHARDT 1966, Samadi und Liebert 2008), die Aminosäurewirksamkeit beim Masthähnchen unter spezifischer Fokussierung der schwefelhaltigen Aminosäuren Methionin und Cystein zu bewerten und neue Erkenntnisse zum Idealprotein-Konzept beim Mastgeflügel zu erhalten. Dazu wurden Stoffwechsel- und Wachstumsversuche mit männlichen Ross 308 Broilerküken in jeweils zwei Altersperioden (Starter- und Growerperiode) durchgeführt. Die Beantwortung der komplexen Fragestellung erforderte ein Herangehen in drei separaten Versuchskomplexen, die folgende Zielstellungen umfassten: Untersuchungskomplex I: Ermittlung des NMR (N-Erhaltungsbedarf) und NRmaxT (theoretisches maximales N-Retentionsvermögen) Untersuchungskomplex II: vergleichende Bertachtung der Methioninwirksamkeit zweier Methioninquellen (DL-Methionin (DLM) und 2-Hydroxy-4-methylthiobuttersäure (MHA)) und Ermittlung des Methioninbedarfs in Abhängigkeit vom Met:Cys-Verhältnis Untersuchungskomplex III: Ableitung eines idealen Aminosäurenverhältnisses unter Betrachtung der Aminosäuren Lysin, Threonin, Tryptophan, Arginin, Isoleucin und Valin Folgende Resultate wurden erzielt: NMR und NRmaxT Der in einem N-Bilanzversuch ermittelte N-Erhaltungsbedarf (NMR) für Ross 308 Broiler betrug für die Altersperiode 10. - 20. LT 295 mg/LMkg0,67 pro Tag und für die Altersperiode 25. - 35. LT 313 mg/LMkg0,67 pro Tag. Da die Ergebnisse, des in beiden Altersabschnitten analysierten N-Erhaltungsbedarfes sehr ähnlich waren, wurde der Mittelwert dieser beiden Parameter eruiert. Der durchschnittliche, als Arbeitswert für den täglichen N-Erhaltungsbedarf angenommene NMR betrug, für die unter der Studie betrachtete Genetik, somit 304 mg/LMkg0,67 pro Tag. Die Bewertung des theoretischen Potentials für die tägliche N-Retention (NRmaxT) männlicher Broilerküken der genetischen Herkunft Ross 308 entsprach für die Altersperiode 10. - 20. LT 3991mg/LMkg0,67 pro Tag und 3110 mg/LMkg0,67 pro Tag für die Altersperiode 25. - 35. LT. Die Ergebnisse demonstrierten, dass das genetische Potential zur Proteindeposition wachsender Broiler mit zunehmendem Alter sank. Methionin-Wirksamkeit Gegenüber der Negativkontrolle konnte durch die DL-Methionin- / MHA-Zulagen bzw. DL-Methionin- / MHA-Zulagen in Kombination mit Cystein der tägliche Zuwachs und der Futteraufwand signifikant verbessert werden. Beim Vergleich der relativen Wirksamkeit von DLM und MHA in dieser Arbeit zeigt sich eine Überlegenheit des DLM in allen Mischungen, mit Ausnahme der zweiten Met+Cys-Supplementationsstufe in der Growerperiode, bei der eine Wirksamkeit von 100 erzielt wurde. Die MHA-Wirksamkeit variierte in einem Bereich zwischen 62% und 100% in Abhängigkeit vom Met:Cys-Verhältnis und dem Gehalt an Met bzw. Cys in der Diät. Die Ergebnisse lassen vermuten, dass mit zunehmendem Anteil an Methionin sowie innerhalb des Methioninlevels ein zunehender Anteil an Cystein in der Diät, die Wirksamkeit von MHA relativ zu DLM senkte. Ableitungen zum täglichen Methioninbedarf Die abgeleiteten Werte zum täglichen Methioninbedarf bezogen sich auf einen Rohproteinansatz von 6 - 10g/d (Starter) bzw. 12 - 20g/d (Grower) und lagen in einem Bereich von: 244 - 498 mg/LMkg0,67pro LT bei einer Met-Wirksamkeit von 157 (Starter, 10. 21. LT) 230 - 500 mg/LMkg0,67pro LT bei einer Met-Wirksamkeit von 196 (Grower, 25. 35. LT) Danach benötigte ein Broiler mit einer mittleren Lebendmasse von 500g zur Realisierung eines täglichen Proteinansatzes von 6 - 10 mg/d eine Zufuhr von 154 313 mg Met/d und ein Broiler mit einer mittleren Lebendmasse von 1800g zur Realisierung eines täglichen Proteinansatzes von 12 20 mg/d eine Zufuhr von 341 742 mg Met/d. Bei einer täglichen Futteraufnahme von 50g bzw. 130g ergaben sich notwendige Aminosäurekonzentrationen im Futter von 0,26 - 0,57% Methionin bzw. 0,31 - 0,63% Methionin. Für die Methioninbedarfswerte zeigte sich eine bestehende Abhängigkeit zum Met:Cys-Verhältnis bzw. Cys-Gehalt der Futtermischung. Ableitungen zum idealen Aminosäurenverhältnis N-Bilanz- und Wachstumsversuche zur Ermittlung der idealen Aminosäurenverhältnisse wurden durchgeführt. Aus den drei N-Bilanzversuchen ergab sich ein ideales Lys:Thr:Trp:Arg:Ile:Val-Verhältnis von 100:61:17:106:59:69 für Broiler in der Altersperiode 10. - 20. LT sowie ein ideales Lys:Thr:Trp:Arg:Ile:Val-Verhältnis von 100:65:17:106:65:82 für Broiler in der Altersperiode 25. - 35. LT. Die Ergebnisse bestätigten die schon für Lys:Thr bekannte Altersabhängigkeit. Neue Aspekte ergaben sich jedoch hinsichtlich Ile und Val, bei denen ebenfalls ein altersbedingter Anstieg relativ zum Lys beobachtet wurde. Unter Mittelwertbildung der beiden Wachstumsversuche ergaben sich folgende Aminosäurenverhältnisse: Lys:Thr:Trp:Arg:Ile:Val von 100:62:18:95:68:72 für Broiler in der Altersperiode 0. - 21. LT und Lys:Thr:Trp:Arg:Ile:Val von 100:73:15:92:73:82 für Broiler in der Altersperiode 21. - 35. LT.