Luis David Solis Murgas

Extrato de orégano como aditivo em rações para frangos de corte

Os objetivos neste experimento foram avaliar os efeitos da inclusao de extrato de oregano (EO) como aditivo promotor de crescimento nas racoes sobre o desempenho, o sistema imune (peso e tamanho da bursa de Fabricius, peso do baco e do timo), as caracteristicas anatomo-fisiologicas do trato gastrointestinal (altura de vilosidade, profundidade de cripta e suas relacoes), a microbiologia do ceco e o pH do duodeno e do ceco de frangos de corte. Foram utilizados 1.440 pintos de corte machos Cobb 500, em duas fases de criacao (1 a 21 e 1 a 42 dias de idade), distribuidos em delineamento inteiramente casualizado, com seis tratamentos e oito repeticoes de 30 aves. Utilizou-se racao basal (RB) para as tres fases de criacao (1 a 21, 22 a 35 e 36 a 42 dias de idade), constituindo os seguintes tratamentos: T1 - RB; T2 - RB com antibiotico (25 ppm de bacitracina de zinco); T3 - RB com 0,025% EO; T4 - RB com 0,050% EO; T5 - RB com 0,075% EO; e T6 -RB com 0,100% EO. Observou-se que os tratamentos nao influenciaram o desempenho e os pHs dos conteudos duodenal e cecal das aves nas duas fases de criacao. As variaveis de imunidade e avaliacao anatomo-fisiologica do trato gastrointestinal aos 21 dias nao apresentaram diferencas. Apenas o peso do baco e a altura de vilosidade aos 42 dias de idade foram influenciados pelos tratamentos. Houve reducao no numero de bacterias no ceco das aves a medida que se elevou o conteudo do extrato de oregano nas racoes, indicando que houve acao antimicrobiana dos componentes deste extrato. Na condicao em que foi realizado o experimento, o uso do extrato de oregano como aditivo promotor de crescimento nao ocasionou efeito diferente dos demais tratamentos (antibiotico e testemunha).

Viabilidade espermática do sêmen de piracanjuba (Brycon orbignyanus) resfriado a 4°C

Os efeitos de tres meios diluidores (BTS+KCl - D1, BTS+2KCL - D2 e BTS+Citrato de Sodio - D3), considerando tres diferentes tempos de resfriamento (0, 72 e 144 horas), foram analizados no semen de Piracanjuba (Brycon orbignyanus) a 4°C. Testou-se, ainda, a utilidade do meio diluidor BTS (Beltsville Thawing Solution), adicionado a citrato de sodio e cloreto de potassio, na manutencao da imobilidade dos espermatozoides e na conservacao de caracteristicas do semen. Resultados satisfatorios foram encontrados ate 144 horas de resfriamento. A motilidade espermatica media do semen in natura foi de 94 ± 5,48%, com duracao media de 55,6 ± 32,25 segundos (s). Para o semen diluido, as medias da motilidade e sua duracao foram de 76,00 ± 1,86% e 56,6 ± 6,54 s, 77,00 ± 1,86% e 54,6 ± 6,54 s, e 74,33 ± 1,86% e 75,0 ± 6,54 s, respectivamente, para os diluidores D1, D2 e D3. Nao houve diferencas significativas entre os diluidores, que apresentaram efeitos semelhantes nos diferentes tempos. As analises nos tempos 0 e 72 horas mostraram motilidades espermaticas superiores aquelas nas 144 horas, embora as duracoes da motilidade espermatica nao tenham diferido nesses tempos. A concentracao espermatica media do semen foi de 8,21 ± 2,26 X 109 sptz/mL. Algumas amostras evidenciaram motilidade espermatica antes da ativacao do semen (pre-ativacao), principalmente a partir das 96 horas de resfriamento. O meio diluidor BTS pode ser recomendado para conservacao de semen de piracanjuba (B. orbignyanus), desde que sua osmolaridade seja elevada.

Criopreservação do sêmen de curimba (Prochilodus lineatus) mediante adição de diferentes diluidores, ativadores e crioprotetores

Semen samples of five specimens of Prochilodus lineatus (Valencienes, 1847) were used to test the toxic and cryoprotectants effects of six solutions based on BTS (Beltsville Thawing Solution®) 4.5%: A - BTS 4.5% + Methanol 10%; B - BTS 4.5% + DMSO 10%; C - BTS 4.5% + KCl 0.072% + Methanol 10%; D - BTS 4.5% + KCl 0.072% + DMSO 10%; E - BTS 4.5% + KI 0.036% + Methanol 10% and F - BTS 4.5% + KI 0.036% + DMSO 10%). The effect of other three activator solutions (Distillated Water, NaHCO3 60 mM and NaHCO3 119 mM) on the rate and duration of sperm motility were also evaluated before and after freezing. No significant differences were observed among the cryoprotectant solutions. Sperm motility rates for P. lineatus were higher for semen activated by NaHCO3 60mM and NaHCO3 119mM, which propitiated the highest sperm motility duration.

Efeito do uso de óleo na dieta sobre a lipogênese e o perfil lipídico de tilápias-do-nilo

A total of 35 males of Nile tilapia, averaging initial weight of 205 g, were maintained in five 250 L metabolism boxes to evaluate the lipid metabolism of Nile tilapias (Oreochromis niloticus). The experiment lasted 30 days, from October to November 2006. The treatments were: control diet plus olive oil; control diet plus corn oil; control diet plus soybean oil; control diet plus linseed oil; control diet plus fish oil. The experiment was in a completely randomized design with five treatments and seven replicates. The evaluated parameters were: fatty acid profile of the muscle tissue and hepatic activity of glucose-6-phosphate dehydrogenase (G6PD) and malic enzyme (ME). The data were submitted to variance analysis and the means of the treatments were compared by Scott-Knotts test (5% of significance). The fish fed on a diet rich in polyunsaturated fatty acids presented increased contents of such fat acids in their lipid muscle composition. The hepatic activity of G6PD was superior to that of ME, being higher in the specimen fed rations containing olive, corn and soybean oil, thus, evidencing the highest lipid muscle deposition of these fish.

Avaliação espermática pós-descongelamento em piracanjuba (Brycon orbignyanus, Vallenciennes, 1849)

The aim of this experiment was to test the effects of two extenders (Glucose 5% and Coconut Water) and two thawing rates (60oC during 5 seconds and 50oC during 10 seconds) for semen of Piracanjuba (Brycon orbygnianus, Vallencienens, 1849). A solution of NaHCO3 1% was used to activate motility. A factorial 2 x 2 was used to analyze the results on sperm motility and its duration, and the percentage of living sperm after thawing. The highest sperm motility values (74.17 ± 22.45%) were achieved when the combination of coconut water and thawing rates of 50oC during 10 seconds was used. The other combinations of extender and thawing rates produced lower sperm motility. The sperm motility duration was not affected by any of the combinations of extenders and thawing rates. The thawing rates showes the average of 153.33 ± 59.61 seconds. The highest percentage of living sperm values (67.83 ± 17.67%) was obtained when the combination of glucose 5% and thawing rates of 50oC during 10 seconds was used. This combination was more effective on the preservation of sperm piracanjuba integrity after freezing.

Utilização de probiótico, prebiótico e simbiótico em rações de leitões ao desmame

Objetivou-se com este trabalho verificar o efeito da suplementacao dietetica de probiotico, prebiotico e simbiotico sobre o desempenho de leitoes desmamados aos 23 dias de idade. Foram utilizados 96 leitoes mesticos desmamados aos 23 dias de idade, com peso medio de 7,40 kg, utilizando-se um delineamento em blocos casualizados com quatro tratamentos, seis repeticoes e quatro leitoes por unidade experimental, para se avaliar o desempenho durante o periodo de 35 dias. As dietas foram isoproteicas e isoenergeticas, formuladas a base de milho, farelo de soja e leite em po modificado, adicionadas de: antibiotico, probiotico, prebiotico ou simbiotico. As dietas foram formuladas para atender as exigencias dos leitoes segundo NRC (1998). Observou-se que os aditivos testados nao influenciaram (P>0,05) o ganho de peso, consumo de racao e conversao alimentar. Conclui-se que a inclusao de probiotico, prebiotico ou simbiotico na alimentacao de leitoes desmamados aos 23 dias de idade proporcionou desempenho semelhante ao obtido com antibiotico.

Role of insulin-like growth factor-I and follicular fluid from ovarian follicles with different diameters on porcine oocyte maturation and fertilization in vitro

The objective of this study was to determine the effects of insulin-like growth factor-I (IGF-I) (0, 60, 120, 180, and 240 ng/mL) and follicular fluid (FF) derived from 2 to 5 and 6 to 10 mm diameter follicles (SpFFs and LpFFs, respectively) added during in vitro maturation (IVM) of porcine oocytes on nuclear maturation and IVF. Cumulus-oocyte complexes (COCs) were matured in NCSU-37 medium supplemented with SpFFs or LpFFs and various IGF-I concentrations. The COCs were cultured for 44 hours, and then fertilized in vitro. Maturation and IVF results were recorded 18 hours after insemination. The IVM (%) was higher (P < 0.05) in the COCs matured in LpFFs than with SpFFs when 0 (90.0 ± 6.9 vs. 76.3 ± 10.7) or 60 ng/mL IGF-I (92.0 ± 8.1 vs. 81.8 ± 10.2) was added. In SpFFs media, there was a quadratic relationship (P < 0.01) between IGF-I concentration and IVM (peak results at IGF-I = 129 ng/mL). However, when the COCs were matured with LpFFs, there was a decreasing linear effect between IGF-I concentration and IVM. At all concentrations of IGF-I, the percentage of degenerated oocytes was higher in COCs matured in SpFFs than in LpFFs. Penetration (%) did not differ (P > 0.05) between COCs matured with SpFFs or LpFFs when 60 (66.8 ± 9.4 vs. 72.7 ± 11.3) or 180 ng/mL of IGF-I (75.7 ± 10.4 vs. 73.8 ± 13.2) were used. Monospermy (%) was similar between SpFFs and LpFFs only with addition of 120 ng/mL IGF-I. The IVF performance (%) did not differ between COCs matured with SpFFs or LpFFs when IGF-I concentrations of 120 (28.5 ± 8.8 vs. 38.5 ± 8.3) and 180 ng/mL (24.3 ± 10.2 vs. 30.12 ± 8.2) were used. There was no effect of IGF-I concentration or of FF type on the number of penetrated sperm per oocyte and on male pronuclear formation. For COCs matured with SpFFs, there was a quadratic relationship between IGF-I concentration and penetration, monospermy, and IVF performance (peak results at IGF-I = 179, 122, and 135 ng/mL, respectively). Thus, on the basis of the observed quadratic relationships, we inferred that when using SpFFs, the addition of IGF-I (122-179 ng/mL) to the IVM medium produced results similar to those obtained with LpFFs without adding IGF-I. In conclusion, the addition of IGF-I to the IVM medium supplemented with SpFFs increased maturation and improved IVF results. Alternatively, IGF-I had no effect on IVM or IVF when used with LpFFs.

Redução do nível de proteína bruta da ração com suplementação de aminoácidos sintéticos para leitões na fase inicial

The effects of reducing dietary CP and soybean meal levels on performance, N excretion, organs weight and diarrhea incident were evaluated in pigs supplemented with amino acids. The diets contained four levels of CP (21.0, 19.5, 18.0, and 16.5%) and were supplemented with synthetic amino acid (lysine, metionine and treonine). In experiment I, eight crossbred (LD x LW) castrated males (initial weight = 22 kg) were individually allotted to a randomized block design, with split plot arrangement to determine N balance. No significant changes in amount of N ingested and excreted in the feces were observed among the treatments. However, the treatments linearly decreased N excreted in the urine, as dietary CP decreased. In experiment II, 60 pigs (initial weight = 8.5 kg) were assigned to a randomized blocks design with 4 x 3 factorial arrangement (four diets and three slaughter ages), with five blocks and one animal per unit experimental, to evaluate the relative weights of liver, spleen and pancreas and intestinal morfometry during the first three post weaning weeks. No significant differences on these parameters were observed across the treatments, whereas crypt depth changed in the first post weaning week, that showed cubic effect. In experiment III, 60 animals (initial weight = 8,0 kg) were allotted to a randomized blocks design, with five blocks and three animals per experimental unit, to evaluate the performance and diarrhea incidence. No significant differences on these parameters were observed across the treatments. Pigs fed diet with 16.5% CP showed decreasing diarrhea incidence. Reducing the dietary CP levels from 21 to 16.5% for pigs in the nursery phase decreased N excretion in the urine and diarrhea incidence with no changes on performance and physiologic parameters of piglets from 8 to 25 kg BW.

Effect of photoperiod on locomotor activity, growth, feed efficiency and gonadal development of Nile tilapia

The objective of this study was to evaluate the effect of photoperiod on locomotor activity, growth and gonadal development in Nile tilapia (Oreochromis niloticus) fingerlings. A completely randomised design was used, with five treatments (0L:24D, 6L:18D, 12L:12D, 18L:6D and 24L:0D) and four replicates, with the aquarium as the experimental unit. One hundred and sixty fingerlings of tilapia weighing 3.21±0.05 g and measuring 4.35±0.07 cm each were distributed among 20 aquaria of 20 L in a recirculation system with the temperature controlled to 27 °C, with eight fish per aquarium. Feeding was carried out twice daily for 75 days, with extruded feed containing 40% crude protein. The fingerlings subjected to a photoperiod of 12L:12D as well as those under 18L:6D and 24L:0D showed the greatest locomotor activity, whereas those under 6L:18D and 0L:24D showed the lowest activity. Fish subjected to a photoperiod of 18L:6D and 24L:0D showed the highest levels of performance. However, manipulation of the photoperiod did not influence the gonadal development, survival or the appearance of deformities in juvenile Nile tilapia. Under long photoperiods (18L:6D and 24L:0D), fish direct their energy to somatic growth and induce best feed efficiency.

Effect of benzocaine concentration and fish size on anesthesia and recovery in Nile tilapia

To evaluate the influence of benzocaine concentration on the induction and recovery from anesthesia in different sized Nile tilapia (Oreochromis niloticus), it was developed a random block experiment design in 4 × 4 factorial consisted of four fish lengths (6; 10; 14 and 18 cm total lenght) and four benzocaine concentrations (60; 120; 180 and 240 mg of benzocaine per liter of water). The induction and the recovery from anesthesia were divided in three stages based on the behavior of the fishes under anesthetic effect. The time spent in each stage was recorded. Differences in length did not affect significantly the anesthesia and recovery time. Linear plateu regressions were generated to estimate the point which increases on anesthetic doses does not imply in further effects. During the anesthesia induction, the plateu occurred in concentration time of 132 mg/L, and estimated time of 86 seconds would be necessary to achieve the complete sedation (stage 3). For permanence of the fish under total sedation, it is needed 190 g/L benzocaine and estimated time of permanence in this stage is 91.1 seconds. Benzocaine concentrations above 190 mg/L do not produce any additional effects that justify its use.