(1). In this thesis the relationship between eggshell quality and bone biology was examined over the laying life of two strains of hen; a highly selected commercial line and the relatively unselected J.Line. (2). The efficiency of using osteocalcin as a marker of osteoid formation, in collaboration with established markers of bone mineralisation and bone resorption, during eggshell calcification was ratified. (3). It was established that magnesium is actively removed from bone hydroxyapatite during resorption and transported to the shell gland pouch for incorporation into the palisade layer of the eggshell. (4). A relationship was demonstrated between hatched eggshell quality and the bone biology of newly hatched chicks. (5). The association between high egg output and poor bone structure was evident in the commercial laying strain hen. No such deficit in skeletal quality occurred in the relatively unselected J.Line. (6). The commercial line demonstrated a significantly higher rate of bone remodelling at late lay concomitant with osteoporosis. (7). The unselected J.Line demonstrated significantly higher rates of bone remodelling throughout lay. It was hypothesised that this was due to a greater propensity for bone upkeep during the inter-egg interval. (8). The provision of a prelay diet influenced neither bone volume nor mineral composition at the beginning of lay. (9). The feeding of a prelay diet led to a longer period of sustained high production and an earlier increase in egg weight. This was accompanied by a delay in the increase in osteoid formation and decreased levels of blood ionised calcium. This led to high "on farm" seconds at late lay due to abnormally high fracture toughness and the Incidence of type B's within the mammillary layer. (10). The reason for the observed decrease in hatchability associated with poorly pigmented eggshells in a commercial guinea fowl flock was related to premature expulsion of the egg. These thinner shelled eggs may have resulted from the process of artificial insemination.

Master of Agribusiness / Department of Agricultural Economics / Allen Featherstone / This thesis addresses the need for a community slaughter facility for poultry. By definition, a slaughterhouse is a place where animals are killed and processed for consumption. The location of the slaughterhouse is located in an area with more than 55% of the Mexican national egg production. This creates an issue regarding disposal of old hens. Old hens create a problem for the industry because their production decreases with age and directly affects the cost and expenses of the operation resulting in a loss of profitability for birds that are not producing at an economic level. In the current situation, hens are discarded, but not in the best ways. Sometimes chickens are killed by asphyxia en masse, or are killed individually by workers. Slaughtered chickens are either buried or burned in big ovens. This current method constitutes a waste product and has negative environmental effects. These issues are corrected via the development of an avian slaughterhouse that will use 100% of hens that are no longer profitable, including the crest, neck, breast, wings, and legs. Products that have been identified for development from “waste” include blood and feather flour; meat flour using the head and intestines; and pasta made from the bones and carcass of the bird. This thesis illustrates the economic feasibility for building the slaughterhouse. In the current environment, value added developments such as this could greatly impact and improve the poultry market in Mexico by increasing competitiveness and benefitting the communities in which such facilities are located.

Antimicrobial growth promoters (AGPs) are substances that are added to feed in sub-therapeutic levels in intensive animal production to improve weight gain and conversion of feed (FCR) into body mass. AGPs have been used widely as growth promoters in broiler and pig production under high-density growth conditions. Despite the observed efficacy, the use of AGPs has been criticized due to its possible role in the development of antibiotic resistance in human pathogens. Directive 183/2003 of the European Parliament, issued in 2003, banned of the use of all antibiotic agents as growth promoters in the European Union from 2006. The new context caused an increase in the search for alternative growth promoters. The aim of this study was to produce a commercially viable prophylactic antibacterial phytogenic product from Ginkgo biloba and Hypericum perforatum with a low potential to develop resistance, as an alternative to AGPs in poultry production. The first objective of this study based on earlier results of the Phytomedicine Programme, was to evaluate the activity and potentize extracts from Ginkgo biloba and Hypericum perforatum for optimal activity against relevant bacterial pathogens. Extracts of ethyl acetate (EA), hexane, dichloromethane (DCM) and acetone (in order of activity) from a direct extraction procedure of powdered G. biloba leaves were active against Enterococcus faecalis, Staphylococcus aureus and Clostridium perfringens. The EA, hexane and DCM extracts were 2 to 3 times more active than the acetone extract (average total activity 1728 ml/g dry extract for the 3 pathogens). The DCM-, EA-, acetone- and hexane extracts (in order of activity) from the direct extraction procedure from H. perforatum were only active against C. perfringens with the first three extracts having a total activity of between 1026 and 1333 ml/g dry material and the hexane extract a total activity of 333 ml/g dry material. The spectrum of activity of G. biloba corresponds to that of Zn-bacitracin, which is commonly used an antibiotic growth promoter in the poultry industry. The second objective in this study was to combine extracts or fractions of extracts of G. biloba and H. perforatum to optimise activity against selected bacterial pathogens. A synergistic effect could be observed when combining a ratio of 1:5 of G. biloba: H. perforatum (hexane extracts) or 1:15 (acetone extracts) against E. faecalis while only an indifferent (neutral) effect was observed against C. perfringens. After elucidation of the quantitative and qualitative aspects involved in the antimicrobial activity, the major antibacterial compound from G. biloba was isolated and characterized as ginkgolic acid (C17:1). It was also determined whether activity against E. faecalis and C. perfringens in an extract or fraction of and extract of G. biloba can be attributed only to ginkgolic acid or whether synergism or other interactions also play a role in the antibacterial activity. It was shown that synergistic interactions are at play between constituents in the hexane and EA fraction, with the last mentioned fraction not containing any ginkgolic acid. These results support the use of the whole extract as opposed to isolated compounds as antimicrobial agents against pathogenic organisms. Two important pharmacodynamic parameters were investigated i.e. resistance development to a hexane extract and the isolated ginkgolic acid from G. biloba against E. faecalis and secondly the time-kill dynamics of this hexane extract over 24 h against E. faecalis. The bactericidal nature of the hexane extract from G. biloba as well the absence of decreased susceptibility to this extract (and the isolated ginkgolic acid) in the resistance studies against E. faecalis indicate that this extract has potential to be exploited as a alternative to AGPs in the poultry industry. The final objective was to determine the effect of extracts of G. biloba alone or in combination with H. perforatum extracts on the performance of broiler chickens over a 35 day period. The effect of these extracts on C. perfringens in the intestine of broilers was also investigated. No significant differences were found with relation to any of the production parameters studied (FCR, live weight or % survival) although a trend towards more favourable European Performance Efficiency Factor index values were observed for treatments containing G. biloba (5% improvement) or a combination of G. biloba and H. perforatum (2.1% improvement) compared to the untreated control. Similarly, Zn-Bacitracin resulted in a 5.5% improvement compared to the untreated control. There was a general trend (not statistically significant, P=0.05) towards a reduction in C. perfringens scores in the feed supplemented with G. biloba- in combination with H. perforatum extract which can probably be ascribed to the direct antimicrobial effect. The rate of colonization was however too low to cause infection probably due to lack of virulence of the C. perfringens challenge and the absence of predisposing factors due to the hygienic growth conditions used. It is necessary for an effective disease model to be developed in order for the efficacy of any new treatment method to be properly evaluated. Such a model will require a much higher incidence of disease and reproducibility than was achieved in this project. The safety of using extracts of G. biloba with ginkgolic acid as the prime antibacterial compound was considered. The active dose was at least 42 times lower than safe dosage recommended in the literature. The combination of extracts of G. biloba and H. perforatum holds promise as a potential growth promoter in poultry production. Better results may be achieved if potentized extracts are used and compared with Zn-Bacitracin and a negative control under industrial growth conditions where the birds are stressed and natural infections would take place. Copyright / Thesis (PhD)--University of Pretoria, 2009. / Paraclinical Sciences / unrestricted

The focus of this study on hedging strategies differs from previous studies in four major ways: l) both costs and selling price are simultaneously hedged, 2) profit margins are computed daily for up to nine months into the future, 3) hedges can be placed five to six months in advance of production, and 4) production costs and profit margins are computed on a weekly basis. Weekly RTC iced broiler production costs were estimated using weekly changes in corn and meal prices and monthly changes in other feed costs, processing costs, transportation and offal value. Weekly production costs were compared to weekly N.Y.C. wholesale broiler prices to determine profit margins. These estimated weekly profit margins served as a benchmark for evaluating alternative hedging strategies. Expected future monthly net profit margins (ENPM) using futures prices and basis estimates for corn, meal, and iced broilers were estimated daily using the production cost formula. The daily ENPM were analyzed to determine their ability to forecast actual profit margins. The ENPM's were poor predictors of actual profit margins. They demonstrated seasonal biases and substantial over and under estimation of actual margins. Forecasted and actual profit margins varied inversely, so positive profit margins were locked in, while negative profit margins were not. Five hedging strategies were developed based on the relationship discovered between expected and actual profit margins. Over the time period 1970-1975, these strategies doubled profit margins and cut profit margin variation substantially. / Master of Science

No description available.

No description available.

Given the drawbacks associated with the use of antibiotics as feed additives and the imminent banning of its use in the European Union, the aim of this project was to develop an extract that could be used as an alternative feed additive in poultry production. The desired extract preferably had to be rich in antibacterial activity to control proliferation of undesired microorganisms, and antioxidant activity to boost the immune system of the poultry. A number of trial extraction procedures were employed on dried leaf material samples to identify the best extraction method. In preliminary extraction studies, direct extraction was performed on leaf samples from the Lowveld National Botanical Gardens (LNBG) and from University of Pretoria Botanical Garden (UP). The principle aim of preliminary studies was to identify the solvents that extracted high antibacterial and antioxidant activity while also extracting large quantities of material. The secondary objective was to test for differences in activities between samples collected from LNBG and UP. Five extractants of varying polarities; acetone, ethanol, ethylacetate, dichloromethane and hexane were used. Antibacterial activity of all extracts was quantified by a serial dilution microplate technique while bioautography was used in qualitative analysis of the antibacterial active compounds. ATCC strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecalis were used as test organisms. Qualitative antioxidant activity was determined by using a DPPH assay on TLC plates. Results from preliminary extraction studies showed larger quantities of material were present in extracts from the LNBG sample than in the UP sample. Two major antioxidant compounds (Rf values of 0.85 and 0.35 in EMW solvent system) were seen on DPPH sprayed TLC plates, while bioautography showed the presence of a number antibacterial active compounds in the acetone, ethanol and ethylacetate extracts with Rr values ranging between 0.85 and 0.56 on TLC plates developed in the EMW solvent system. MIC values of the extracts tallied with the results from bioautography. The acetone, ethanol and ethyl acetate extracts had the highest antibacterial activity while the hexane extracts had the lowest activity with average MIC value of 0.55 mg/ml for both the LNBG and UP samples. MIC values as low as 0.04 mg/ml were measured in the acetone and ethylacetate extracts of the LNBG sample against S. aureus and E. faecalis. Based on results from preliminary extraction studies, hexane was identified as a possible pretreatment solvent for application in enrichment procedures, acetone and ethanol were chosen as the main extractants and only the LNBG sample was used for future work. Enrichment procedures were employed along two pathways; the first pathway involved the use of hexane "wash" as a pretreatment procedure prior to extraction with acetone or ethanol. The second pathway involved the use of various mixtures of acetone in water and ethanol in water as extractants. The rationale of using these various ratios was an attempt to identify solvent mixtures that would selectively extract the bioactive components or otherwise selectively remove inactive material. A serial dilution microplate method was used to determine Minimum Inhibitory Concentrations (MICs) and the Trolox Equivalent Antioxidant Capacity (TEAC) assay was used to quantify antioxidant activity of all extracts. The optimal extract was the one developed by pretreatment with a single direct extraction with hexane prior to extraction with acetone. It had a TEAC value of 2.3, an increase in TEAC value of 283% compared to that of the crude acetone extract. The average MIC of the crude acetone extract against ATCC stains of S. aureus, Ps. aeruginosa, E. coli and E. faecalis had dropped from 0.15 mg/ml to 0.08 mg/ml in the optimal extract (an improvement in antibacterial activity of 87.5%). Since the optimal extract is intended for commercial application in poultry production, its antibacterial activity was tested against Campylobacter jejuni, Clostridium perfringens, Salmonella enteritidis, E. coli and multi drug resistant E. coli isolated from chickens. Its in vitro toxicity was ascertained using the brine shrimp assay and the MTT cytotoxicity assay on monkey kidney cells. The optimal extract was effective against Campylobacter jejuni and Clostridium perfringens with MIC values ranging from 40 µ/ml to 80 µ/ml. It was also active against multi-resistant strains of E. coli and Salmonella enteritidis (MIC values of 125 µ/ml for both strains). LC50 results from the brine shrimp assay and the MTT cytotoxicity assay on monkey kidney cells gave values of 863 µ/ml and 226 µ/ml respectively indicating low toxicity. These results meant that though in some cases the MICs of the optimal extract were higher than befitting of typical antibiotics, due to its relatively low toxicity, large quantities of the extract may possibly be feed to achieve the desired activity without causing any toxicity in the poultry. The major antioxidant compound was isolated by silica gel column chromatography. The isolated compound was identified by nuclear magnetic resonance and mass spectroscopy as combretastatin BS (2', 3', 4-trihydroxyl, 3, S, 4'-trimethoxybibenzyl), previously isolated from the seeds of C. kraussii and also from C. woodii leaves. Famakin (2002) showed this compound to be the major antibacterial compound in C. woodii leaves. Combretastatin BS (CBS) demonstrated in vitro cytotoxicity in the MTT assay on monkey kidney cells with an LC50 value of 1 0 µ/ml. In vitro cytotoxicity of CBS could be due to its antimitotic activity. The TEAC value of 7.9 found in this study means that combretastatin BS has about 8 times the antioxidant capacity of vitamin E. This is the first report of the antioxidant activity of any of the combretastatins. Tolerance of broiler chickens to the optimal extract was assessed at clinically inferred doses of 2 mg/kg, Smg/kg and 10 mg/kg . After 21 days of infeed-dosing with the optimal extract, none of the chickens died or showed any behavioral signs of toxicity. There were no statistically significant differences in weight gain between broilers fed the optimal extract and the positive and negative control. There was also no positive correlation between weight gain and amount of the optimal extract incorporated in feed. Although the optimal extract did not result in significant growth promotion relative to the positive and negative control, 2 mg/kg dose regimens showed the best Feed Conversion Ratio (FCR), with a 6.2% improvement compared to the negative control. The positive control was the only other feed regimen to provide a positive FCR with an improvement of 1.73% compared to the negative control. Because purchase of feed could represent up to 80% of costs of broiler production, this is an important finding. If these results can be confirmed, the product may therefore have commercial value. Repetition of the experiment with lower doses of the optimal extract on poultry challenged with bacterial infections is required to confirm the commercial applicability of this product. Copyright / Dissertation (MSc (Paraclinical Science))--University of Pretoria, 2004. / Paraclinical Sciences / unrestricted

Visando investigar a dinâmica locacional das empresas dos complexos aves e suínos estabelecidas na região Centro-Oeste brasileira, foi conduzida uma pesquisa empírica do processo de decisão locacional e dos fatores-chave na escolha do local produtivo, tendo como referencial teórico uma abordagem comportamental da Teoria da Localização. A pressuposição central deste estudo é a de que os preços mais baixos das matérias-primas básicas (em especial o milho) nos estados da região Centro-Oeste não são suficientes para explicar o desenvolvimento das atividades dos complexos de aves e suínos nessa região. O método de pesquisa empregado foi o de questionário, enviado para as 46 empresas de aves e suínos presentes no Centro-Oeste no segundo semestre de 2000, contemplando basicamente duas classes de variáveis, as de decisão e as locacionais. Pelo fato de as variáveis terem sido do tipo qualitativas, o instrumental analítico adotado foi a análise de tabelas de contingência, sendo a independência entre os pares de variáveis avaliada através de testes de hipótese. Com taxa de retorno dos questionários de aproximadamente 59%, detectou-se, dentre as principais características das empresas, que 74% instalaram-se na região na década de 90; 40% são empresas grandes, 30% médias e 30% pequenas; 64% das empresas constituíam-se em um novo negócio ou em uma expansão de uma empresa regional, sendo que 45% das primeiras tiveram empresários oriundos de regiões fora do Centro-Oeste; 83% da capacidade de abate de aves e suínos está concentrada nas empresas integradoras. Apesar de a estatística descritiva ter sugerido que as empresas grandes, integradoras e oriundas de outras regiões que não o Centro-Oeste tivessem apresentado maior esmero na pesquisa locacional - em termos da abrangência e tempo da pesquisa, das informações e estudos utilizados, da escolha ou não pela última alternativa pesquisada e da elaboração de perfil prévio da localização almejada - os testes de hipótese não significativos acarretaram na não rejeição de independência entre as variáveis. Já a característica meta do empresário, que conseguiu determinar um agrupamento prévio das empresas que as fizesse diferir em seu processo de decisão locacional, em especial entre os grupos de empresas categorizadas com as metas minimizar custos de abastecimento de matérias-primas e apenas iniciar uma atividade produtiva como outra qualquer, apresentou testes significativos. Assim, seja a empresa grande ou integradora, o fato dela ter explicitado não haver uma clara pretensão em estar iniciando, expandindo ou relocalizando sua atividade produtiva no Centro-Oeste, denota a sua pequena preocupação com a localização. Com relação aos fatores locacionais determinantes do local da escolha, foi claro o desequilíbrio entre o elevado nível de importância atribuído ao vetor matérias-primas para com os outros. Os resultados obtidos permitem concluir que o milho de fato age como norteador das atividades de aves e suínos na região Centro-Oeste, configurando-se não somente como fator de atração às empresas, mas também como elemento naturalmente causador de atividades sinérgicas de agregação de valor a jusante da produção. / With a view to research the location dynamics for poultry and hog-raising companies in the Brazilian Midwest, an empiric survey was carried out about the location decision-making, with a behavioral approach to the Localization Theory serving as a theoretical benchmark. The core assumption in this survey is that lower prices for basic input (particularly corn) in the Midwestern states are not enough to explain the development in the poultry and hog complexes in that region. The research method employed was a questionnaire, sent to the 46 poultry and hog companies operating in Midwestern Brazil in the second half of 2000, taking into account, basically, two classes of variables - the ones relating to decision-making and the ones relating to location. Because the variables contemplated are qualitative, the analytical tool set adopted was an analysis of contingency tables, with the interdependence between pairs of variables evaluated through test hypotheses. With an approximate 59% return on questionnaires sent, it has detected, among other main traits for the corporations, that 74% of them entered the region in the 90s; 40% are big, 30% medium and 30% small companies; 64% of them were new businesses or expansions of regional companies, and 45% of the first group were commanded by businessmen from outside the Midwestern region; 83% of the slaughtering capacity for poultry and hogs is concentrated on integrators. Although descriptive statistics suggest that big, integrator companies coming from outside Midwestern Brazil have dedicated more effort to location research - in scope and research time; information and studies employed; whether the alternative selected was the last one to be considered; and the previous creation of a profile for the desired location -, the non-significant hypotheses tests denied a dependence between variables. On the other hand, the trait selected as a goal by businessmen, which has resulted in a previous grouping of companies with differences on their location selection process, particularly among companies which had as goals minimizing their raw material costs or only to begin a production activity of whatever kind, has presented significant test results. Thus, albeit the company is big or an integrator, the fact that it has explicitly claimed that it did not intend to begin, expand or relocate activities to Midwestern Brazil shows its lack of care about location. Regarding the location factors that determined a location selection, there was a clear lack of balance between the high importance attributed to the raw material vector and most any other factor. The results obtained allow to conclude that corn is in fact a defining factor for poultry and hog-raising activities in the Midwest, serving not only as an attraction factor for companies but also as en element which naturally brings synergetic value-adding activities as an accessory to production.

Os prejuízos causados por Escherichia coli patogênica para aves (APEC) na produção de aves é justificativa de pesquisas realizadas no mundo todo há décadas. Recentemente, o potencial zoonótico e a multirresistência das cepas desse patotipo têm sido alvo frequente dos trabalhos realizados com APEC. O objetivo desse trabalho foi caracterizar 225 cepas APEC isoladas de perus condenados por aerossaculite em abatedouros em relação à resistência a 14 antimicrobianos, perfil de virulência e grupos filogenéticos. 92% das amostras apresentaram perfil de multirresistência (MDR) e os índices mais altos de resistência foram a sulfonamidas (94%), tetraciclina (83%), eritromicina (82%), estreptomicina (60%), amoxicilina (53%) e ácido nalidíxico (48%). Metade das cepas foram classificadas no grupo filogenético B2 (50%), seguido por B1 (28,6%), grupo A (17,1%) e grupo D (4,8%). Os genes de virulência pesquisados tiveram prevalência de iroN (95%), iss (93%), cvi/cva (67%), iucD (67%), tsh (56%), irp2 (51%), ibeA (31%), vat (24%), neuS (19%), astA (17%) e papC (15%). Considerando o potencial zoonótico e a associação a um maior número de genes de virulência quando comparadas aos outros grupos filogenéticos, as cepas B2 foram selecionadas para pesquisa de integrons de classe 1 e clonalidade. As 112 amostras B2 eram pertencentes a 83 diferentes perfis ERIC, sendo classificadas como multiclonais. Os integrons de classe 1 estiveram presentes em 107 isolados (95,5%). Esses resultados demonstram que a maioria das cepas pesquisadas pertencia ao grupo mais virulento (B2) e relacionado a cepas ExPEC humanas. Aliado ao alto índice de multirresistência encontrado, esses dados sugerem que as aves podem servir como reservatório de cepas patogênicas e multirresistentes, tanto para humanos como para animais, reforçando a ideia de que as aves representem importante papel na cadeia epidemiológica das ExPEC. / Avian Pathogenic Escherichia coli (APEC) has been studied for decades because of its economic impact on the poultry industry. Recently, the zoonotic potential of APEC and multidrug-resistant strains have emerged. The aim of this study was to investigate the virulence profile, phylogenetic background and antimicrobial resistance in 225 strains of Escherichia coli isolated from turkeys presenting airsacculitis. The results showed that 92% of strains presented a multidrug-resistance (MDR) profile, and the highest levels of resistance were to sulfamethazine (94%), tetracycline (83%). Half of these strains (112/225) were classified in phylogenetic group B2, followed by groups B1 (28.6%), A (17.1%) and D (4.8%). The prevalence of virulence genes was as follows: iroN (95%), iss (93%), cvi/cva (67%), iucD (67%), tsh (56%), irp2 (51%), ibeA (31%), vat (24%) neuS (19%), astA (17%) and papC (15%). Considering the zoonotic potential and association to a greater number of virulence genes when compared to other phylogenetic groups, B2 strains were selected for screening of class 1 integrons and clonality. The 112 samples belonging to 83 ERIC profiles and classified as multiclonal. Class 1 integrons were present in 107 isolates (95.5%).These results demonstrate that the majority of the investigated strains belonged to group B2, which is more virulent and is related to human ExPEC strains. Coupled with the high rate of multidrug-resistance found, these data suggest that turkeys may serve as a reservoir for pathogenic and multidrug-resistance strains, for humans and animals, reinforcing the idea that poultry plays an important role in the epidemiological chain of ExPEC.

Dois experimentos foram realizados para avaliar o efeito da alimentação sequencial (AS) no desempenho e metabolismo energético e proteico de frangos de corte e suínos em crescimento. No primeiro experimento foram utilizados 144 frangos de corte com 21 dias de idade, alojados em baterias de metabolismo. As dietas A e B foram formuladas para atender 100% e 80% das recomendações de aminoácidos digestíveis, respectivamente. Os tratamentos utilizados foram: Tratamento AA, dieta A, fornecida durante todo o ciclo de 24 horas; Tratamento AB, dieta A fornecida durante o dia e dieta B fornecida durante a noite; Tratamento BA, dieta B fornecida durante o dia e dieta A fornecida durante a noite e; Tratamento BB, dieta B fornecida durante todo o ciclo de 24 horas. No experimento com suínos foram utilizados 16 animais com peso inicial de 30 kg, alojados em gaiolas metabólicas. Os tratamentos e as dietas experimentais seguiram as mesmas proposições do experimento com aves, porém com parâmetros nutricionais ajustados para suínos. Os frangos submetidos à AS apresentaram desempenho semelhante à dieta completa, com ligeira piora na conversão alimentar. Os frangos de corte dos tratamentos com AS ingeriram menos energia, nitrogênio (N) e lisina comparadas aos animais alimentados exclusivamente com a dieta A. Os valores de retenção e excreção de N nos frangos alimentados sob regime de AS compararam-se ao tratamento AA. O tratamento BA excretou menos N e obteve uma relação de retenção de N por quilograma de peso vivo equivalente ao tratamento AA. Em suínos, não foram detectados efeitos da AS sobre o peso final, consumo de ração diário, ganho de peso diário e conversão alimentar. A ingestão de N foi influenciada pela AS, mas não houve diferença na excreção e retenção de N, comparado ao tratamento AA. Os programas de AS apresentam desempenhos similares com reduzida ingestão de nutrientes e retenções de N similares a programas de alimentação convencionais em frangos de corte. AAS mantém o potencial de retenção de nitrogênio de uma dieta convencional, sem alterar os coeficientes de digestibilidade da dieta e o desempenho zootécnico. O fornecimento da dieta deficiente em aminoácidos durante o período da noite parece ser a melhor escolha para otimizar retenção de nitrogênio ao aplicar a estratégia de alimentação sequencial em suínos. / Two experiments were carried out to evaluate the effect of sequential feeding (AS) on performance and energy and protein metabolism of broiler chickens to growing pigs. In the experiment in birds were used 144 broiler chickens with 21 days of age, housed in metabolism batteries. Diets A and B were formulated to meet 100% and 80% of digestible amino acid recommendations, respectively. The treatments utilized were: Treatment AA, diet A, provided throughout the 24-hour cycle; AB treatment, A diet provided during the day and diet B provided overnight; Treatment BA, diet B provided during the day and diet A provided at night and; Treatment BB, diet B provided throughout the 24 hour cycle. In the experiment with pigs were used 16 animals with initial weight of 30 kg, housed in metabolic cages. The treatments and the experimental diets followed the same propositions of the experiment with birds, however with nutritional parameters adjusted for pigs. The birds submitted to AS presented similar performance to the complete diet, with a slight worsening in feed conversion. The birds in the AS treatments ingested less energy, nitrogen (N) and lysine compared to birds fed exclusively on diet A. The N retention and excretion values in the birds fed under AS regimen were compared to the AA treatment. The BA treatment excreted less N and had a N retention ratio per kilogram live weight equivalent to the AA treatment. In pigs, no effects of AS and final weight, daily feed intake, daily weight gain and feed conversion were detected. N intake was influenced by AS, but there was no difference in N excretion and retention compared to AA treatment. AS programs perform similar performances with reduced nutrient intakes and N retention similar to conventional feeding programs in broilers. AS maintains the nitrogen retention potential of a conventional diet without altering the digestibility coefficients of the diet and the zootechnical performance. The supply of the amino acid deficient diet over night appears to be the best choice to optimize nitrogen retention by applying the sequential dietary strategy.