Ammonia levels on in vitro degradation of fibrous carbohydrates from buffel grass

This study was carried out to examine the degradation dynamics of neutral detergent fibre (NDF) and the profile of volatile fatty acids that originate from the fermentation of buffel grass (Cenchrus ciliaris, L.) with various levels of ammonia in the growth medium. The treatments consisted of six levels of ammonia in the growth medium (0, 5, 10, 15, 20 and 30 mg/dL), which were obtained by adding urea. These in vitro incubation times were evaluated in three replicates per time for 0, 3, 6, 9, 12, 24, 36, 48, 72 and 96 hours. Rumen concentrations of acetate and propionate responded quadratically to the ammonia levels. The treatment with 15 mg/dL of ammonia nitrogen in the rumen fluid provided mean acetate and propionate contents of 57.6 mM and 23.1 mM, respectively. Urea addition elevated the degradation rate of potentially degradable fraction of NDF (pdNDF) from 2.5% to 20.1% in comparison with the treatment without urea and to a reduction in estimated discrete lag time from 0.34 to 2.31 hours. Urea supplementation increased the specific microorganism growth rate from 2.6% to 20.1%. At the end of the incubation trial, NDF degradation showed a quadratic response, with maximum value obtained at 17.76 mg/dL of ammonia in the rumen fluid. Urea improves the degradation dynamics of NDF from deferred buffel grass and increases the concentrations of acetate and propionate.Keywords: Cenchrus ciliaris, degradation kinetics, non-protein nitrogen, ure

Effect of salt concentrations on in vitro rumen fermentation of cellulose, starch, and protein

The aim of this study was to evaluate the effects of various concentrations of three salts (sodium chloride (NaCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2)) on the in vitro rumen fermentation of cellulose, starch, and protein substrates. Six salt concentrations were tested, separately, namely 0, 100, 200, 400, 800, and 1600 mg/dL. The experiment was conducted using the completely randomized design in a 6 × 3 × 3 factorial arrangement with main effects of salt concentration and salt type (six levels of three salts (NaCl, MgCl2, or CaCl2) (0, 100, 200, 400, 800, and 1600 mg/dL) into three substrates [starch, cellulose, and glucose]) with three replicates. Cellulose- and glucose-fermenting bacteria were sensitive to NaCl concentrations greater than 400 mg/dL (17.48 decisiemens per metre (dS/m)) and 800 mg/dL (20.55 dS/m) in the media, respectively. In contrast, starch-fermenting bacteria continued to grow in NaCl concentrations up to 1600 mg/dL (29.09 dS/m). Thus, it was concluded that starch-fermenting microorganisms tolerated higher concentrations of NaCl compared with the other microbial groups. Cellulose-fermenting microorganisms are less tolerant to MgCl2 in relation to the other microbial groups. Starch, cellulose-, and glucose-fermenting bacteria from cattle tolerate CaCl2 concentrations of up to 1600 mg/dL (12.26 dS/m). These results suggest that brackish water may be used for ruminants. However, it is important perform an analysis of that water and then to adjust diets to minimize the effects of types of salt and concentrations of salt on rumen microorganisms. Keywords: brackish water, dissolved salts, rumen microbes, water qualit

Fermentation characteristics and chemical composition of elephant grass silage with ground maize and fermented juice of epiphytic lactic acid bacteria

This study aimed to evaluate the microbial populations, fermentation profile, dry matter recovery and chemical composition of elephant grass silage with ground maize (GM) and the fermented juice of epiphytic lactic acid bacteria (FJLB). A factorial design was used with four levels of GM (0 g/kg, 50 g/kg, 100 g/kg and 200 g/kg), untreated or treated with FJLB, in a completely randomized design with five replicates. A pre-experiment was undertaken to determine the optimum level of sucrose to be added to fermented juice for the development of epiphytic microflora. In this pre-experiment, a completely randomized design with three replications was used. The treatments were represented by the levels of sucrose (0 g/kg, 5 g/kg, 10 g/kg, 20 g/kg, 40 g/kg, 60 g/kg and 80 g/kg, fresh matter basis). The microbial populations, dry matter recovery, and effluent losses were affected by the interaction between GM and FJLB. Dry matter (DM) and crude protein (CP) contents increased linearly with the inclusion of GM. The addition of GM enhanced the fermentation process via a reduction in losses, and improvements were identified in the nutritional value of elephant grass silages. The use of fermented juice increased dry matter recovery, and its effect was more pronounced when ground maize was added.Keywords: dry matter recovery, lactic acid, microbiology, Pennisetum purpureu

Morfogênese e estrutura de brachiaria decumbens em resposta ao corte e adubação nitrogenada

Aimed to evaluate the morphogenetic and structural characteristics of the pasture of Brachiaria decumbens, subjected to several intensities and frequencies of cutting and nitrogen fertilization. Experimental design was randomized blocks in split plots, whit a 2 x 2 factorial arrangement relating to combinations of two cutting heights (40 and 50 cm) and two heights of residue (15 and 25 cm) at the plots and nitrogen fertilization (with or without nitrogen) in sub-plots, with four replications. Mophogenetic variables evaluated were: leaf elongation rate (LER), stem elongation rate (SER), leaf appearance rate (LAR), leaf senescence rate (LSR) and phyllochron; and structural features were: number of basal tillers (NBT), total number of leaves (TNL), number of leaves appeared (NLAp), number of dead leaves (NDL), number of alive leaves (NAL) and final leaf length (FLL). 100 kg N/ha allowed increase (p<0.10) on LER of 31.58% and 126.32% respectively for residues 15 and 25 cm. The NBT compared to cutting heights (40 to 50 cm) were affected (p<0.10) only with the use of nitrogen fertilizer, with average of 145.62 tillers/m 2 in 50 cm cut height. Residue height of 25 cm combined with cut height 40 cm increase leaf elongation rate and number of basal tillers, reducing expansion time, without changing other structural characteristics of the pasture.Objetivou-se avaliar as características morfogênicas e estruturais do pasto de Brachiaria decumbens, submetido a intensidades, fre- quências de corte e adubação nitrogenada. O delineamento experimental foi em blocos casualizados em esquema de parcelas subdividi- das, tendo na parcela o arranjo fatorial 2 x 2 referente a combinações entre duas alturas de corte (40 e 50 cm) e duas alturas de resíduo (15 e 25 cm) e nas sub-parcelas a adubação nitrogenada (com ou sem nitrogênio), com quatro repetições. As variáveis analisadas para as ca- racterísticas morfogênicas foram: taxa de alongamento foliar (TAlF); taxa de alongamento de colmo (TAlC); taxa de aparecimento foliar (TApF); taxa de senescência foliar (TSF) e filocrono; e para as características estruturais foram: número de perfilhos basais (NPB); número de folhas totais (NFT); número de folhas aparecidas (NFAp); nú- mero de folhas mortas (NFM); número de folhas vivas (NFV) e comprimento final da folha (CFF). A utilização de 100 kg/ha de N permitiu aumento (p<0,10) na TAlF de 31,58% e 126,32%, respec- tivamente para os resíduos de 15 e 25 cm. O NPB em comparação às alturas de corte (40 e 50 cm) foi afetado (p<0,10) apenas com a utilização da adubação nitrogenada, observando-se média de 145,62 perfilhos/m 2 para a altura de corte 50 cm. A altura de resíduo 25 cm combinada com a altura de corte 40 cm, junto à aplicação de 100 kg/ha de N, promovem maior produção de matéria seca total em menor espaço de tempo (28 dias), permitindo maiores taxas de lotação e facilitando o manejo no sistema de lotação rotacionada

Cinética de fermentação ruminal in vitro de silagens de híbridos de sorgo

Objetivou-se com esta pesquisa avaliar as silagens de 23 híbridos de sorgo por meio da técnica in vitro semiautomática de produção de gases. Foi utilizado o delineamento inteiramente ao acaso, com 23 tratamentos e três repetições, sendo os tratamentos as silagens de híbridos de sorgo. Os híbridos foram cultivados na estação experimental do Instituto Nacional do Semiárido (INSA), no município de Campina Grande - PB. A produção de gases foi estimada por intermédio do modelo logístico bicompartimental, ajustado às curvas de produção cumulativa de gases. Com relação ao volume final de carboidratos fibrosos (VfCF), houve efeito de híbrido (P<0,05), com resultados variando de 105,99 a 144,53mL/g de MS. Os valores de taxa de degradação dos carboidratos fibrosos (KdCF) variaram (P<0,05), e o híbrido 866041 apresentou o maior resultado 0,015h-1. Os valores de volume final total (VfT) variaram (P<0,05), e os híbridos 870085, Volumax e XBS 60329 apresentaram maiores (P<0,05) valores de VfT em relação aos demais. Pela análise multivariada, foram formados seis grupos distintos. O grupo 2, composto pelos híbridos 22 (Volumax) e 23 (XBS60329), apresentou os maiores valores médios para os volumes de gás, tanto para os carboidratos fibrosos quanto para os não fibrosos. O grupo 4, composto pelo híbrido 1 (866005), apresentou as menores médias para volume de gás produzido e o maior lag time (3,15 horas). Todos os híbridos estudados apresentam potencial para ensilagem, de acordo com a cinética de fermentação ruminal

Biofloc technology on the zootechnical performance of tilapia: effect of strain and stocking density

The necessity of new technologies for the culture of aquatic organisms is becoming more evident, and thus, the biofloc system, a technic created to perform zero or minimum water exchange, starts to become more useful not only in shrimp culture, but also in finfish culture. This research purpose was to evaluate the growth and survival of Nile tilapia or “gray” (Oreochromis niloticus – GIFT strain) and red tilapia “Red Florida” strain (Oreochromis sp.) in biofloc system stocked in different densities (400 e 800/m3) in brackish water (8‰). Sixteen 26L plastic bins (19L usefull) were used and 192 fingerlings (3,06 ± 0,2 g) were stocked. A factorial experimental design was adopted (strain vs density) and a “macrocosm-microcosm” device system. For42 days, the animals were fed on a 45% CP commercial diet, three times per day. Water quality parameters and microbial community were monitored. At the end, proximate analysis of biofloc biomass was performed. The results suggested that Nile tilapia was the most appropriate for this phase (3-20 g) in biofloc system in brackish water. Furthermore, no negative effect was observed when 800 fish/m2 stocking density was considered.A necessidade de novas tecnologias para o cultivo de organismos aquáticos se faz cada vez mais presente, assim, o sistema de bioflocos, tecnologia concebida para trabalhar com nenhuma ou pouca renovação de água, começa a ter uso não somente na carcinicultura, mas também na piscicultura. O presente trabalho teve como objetivo avaliar o crescimento e sobrevivência de tilápias do Nilo (Oreochromis niloticus – linhagem GIFT) e tilápia vermelha (Oreochromis sp.) em sistemas de bioflocos sob diferentes densidades de estocagem (400 e 800/m3) em água salobra (8‰). Foram utilizadas 16 caixas plásticas de 26L (19L útil) e estocados 192 alevinos (3,06 ± 0,2 g). Adotou-se um delineamento fatorial (linhagem x densidade) e um sistema macrocosmo-microcosmo. Durante 42 dias os animais foram alimentados três vezes ao dia com ração comercial contendo 45% de proteína bruta. Foram monitorados os parâmetros de qualidade de água e o perfil de microrganismos da mesma ao longo do experimento. No final, foi realizada uma análise bromatológica da biomassa de bioflocos. Os resultados sugerem a tilápia do Nilo (O. niloticus) a mais adequadas para esta fase (3-20 g) em um sistema de bioflocos em água salobra. Observou-se ainda que não houve efeito negativo no crescimento quando empregado densidade de 800 peixes/m³