Evaluation of Increasing Dietary Concentrations of a Multi-Enzyme Complex in Feedlot Lambs' Rations.

The objective of this study was to evaluate the effects of increasing levels of the M-E complex (xylanase, glucanase, cellulase, and invertase) Optimax E® on the performance of growing lambs, their digestibility, and their rumen microbiota, and to estimate NEm, NEg, and ruminal methane levels. Forty lambs (Katahdin x Dorset; 22.91 ± 4.16 kg) were randomly assigned to dietary concentrations of ME (0, 0.2, 0.4, and 0.8% DM) and fed individually for 77 days. Increasing M-E improved feed conversion (p < 0.05) as well as NEm and NEg (p < 0.05), which were associated with increased in vivo DM and NDF digestion (linear and quadratic p < 0.01). Few microbial families showed abundancy changes (Erysipelotrichaceae, Christensenellaceae, Lentisphaerae, and Clostridial Family XIII); however, the dominant phylum Bacteroidetes was linearly reduced, while Firmicutes increased (p < 0.01), resulting in a greater Firmicutes-to-Bacteroidetes ratio. Total Entodinium showed a quadratic response (p < 0.10), increasing its abundancy as the enzyme dose was augmented. The daily emission intensity of methane (per kg of DMI or AGD) was reduced linearly (p < 0.01). In conclusion, adding the M-E complex Optimax E® to growing lambs' diets improves their productive performance by acting synergistically with the rumen microbiota, modifying the Firmicutes-to-Bacteroidetes ratio toward more efficient fermentation, and shows the potential to reduce the intensity of greenhouse gas emissions from lambs.

Phytogenic additive from Prosopis juliflora on populations of rumen ciliate protozoa and its correlation with nutrition of sheep.

We evaluated the effect of phytogenic additive Prosopis juliflora on populations of ruminal ciliated protozoa and its correlation with variables related to sheep nutrition. In this experiment, five cannulated adult Santa Ines ewes were submitted to the additive intake. Each animal received 6 mL of the extract daily. The experimental design adopted was the Latin square 5 × 5 (five concentrations of additive 0, 200, 400, 600 and 800 mg/mL of water and five periods of 18 days). The additive quadratically reduces the number of large, small and total ciliating protozoa, without promoting changes in the number of medium protozoa in the rumen. Among the genera investigated, Isotricha and Dasytricha were the only ones affected by supplementation. Additionally, the concentration of ruminal protozoa correlates significantly with the variables related to the nutrition of the animal. The effects of the additive on these variables were particularly pronounced at concentrations around 600 mg/mL.

O efeito de probióticos fúngicos adicionados a uma dieta rica em grãos no trato gastrointestinal de ovinos / The effect of fungal probiotics added to a high-grain diet on the gastrointestinal tract of sheep

This study aimed to evaluate the microbiological and physicochemical characteristics of the ruminal fluid and histological characteristics of the gastrointestinal tract (GIT) of sheep on a high-grain diet containing the probiotic fungi Aspergillus terreus and Rhizomucor spp. The study included four treatment groups (without probiotic, with Rhizomucor spp., with Aspergillus terreus, and with a mixture of both fungi), and two types of corn (ground/whole), in a Completely Randomized Design (CRD) arranged in 4 x 2 factorial design. Santa Inês x Dorper lambs were housed in eight pens with five lambs each for 75 days. Rumen fluid was collected to study the rumen microbiological profile, macroscopic characteristics, ammonia nitrogen concentration, and microbiological activity. In addition, GIT samples were taken for histological analysis. Fluid analyses showed that the animals presented a low acidosis index. The samples presented a predominantly aromatic odor and blackish-brown color, indicating a neutral pH and high microbial activity. The rumen pH differed (P < 0.05) according to the level of processed corn consumed, being higher for ground grain corn (GGC). There was no difference for any of the microbiological communities analyzed (P > 0.05) (Lac+ and Lac- bacteria, fungi, yeasts, and protozoa). Six genera of facultative anaerobic fungi were identified in 15 observations. Cladosporium spp. was the most prevalent genus (46.66%), followed by Aspergillus spp. (26,66%). The width of the base of rumen papillae showed significant correlation being greater for GCG (P < 0.05) with Rhizomucor and for the control (P < 0.05). The rumen fluid of sheep on a high-grain diet with added Aspergillus terreus and Rhizomucor spp. showed no microbiological and physicochemical changes.

Objetivou-se avaliar as características microbiológicas e físico-químicas do fluido ruminal e histológicas do trato gástrico intestinal (TGI) de ovinos sob dieta de alto grão com probiótico fungos Aspergillus terreus e/ou Rhizomucor spp. Analisou-se quatro probióticos (sem inóculos, com Rhizomucor spp., com Aspergillus terreus e com mistura dos dois fungos) e dois processamentos de milho (moído/inteiro), em fatorial 4x2 em em Delineamento Inteiramente Casualizados (DIC). Borregos Santa Inês/Dorper foram alojados em oito baias com cinco borregos em cada, durante 75 dias. Coletou-se fluido ruminal para o estudo do perfil microbiológico do rúmen, da característica macroscópica, da concentração de nitrogênio amoniacal e da atividade microbiológica, além dos fragmentos do TGI para análises histológicas. Pelas análises dos fluidos, os animais apresentaram baixo índice de acidose. O odor aromático e a cor castanho-enegrecido predominaram, o que caracteriza ambiente com pH neutro. As amostras do fluido apresentaram alta atividade microbiana. O pH ruminal diferenciou-se (P<0,05) quanto ao tipo de processamento, sendo maior para milho grão moído (MGM). Não houve diferença para nenhuma das comunidades microbiológicas analisadas (P>0,05) (bactérias Lac+ e Lac-, fungos, leveduras e protozoários). Seis gêneros de fungos anaeróbicos facultativos foram identificados num total de 15 observações. O Cladosporium spp. foi o gênero mais prevalente (46,66%), seguido do Aspergillus spp. (26,66%). A largura da base das papilas ruminais apresentou interação significativa, sendo maior para MGM (P<0,05) com Rhizomucor e o controle (P<0,05). O fluido ruminal de ovinos sob dieta de alto concentrado de grão com adição dos fungos Aspergillus terreus e Rhizomucor spp. não tiveram afetadas as características microbiológicas e físico-químicas.

Altered milk yield and rumen microbial abundance in response to concentrate supplementation during the cold season in Tibetan sheep

BACKGROUND Weight loss and decline of milk yield in Tibetan sheep was a challenge for the dairy industry in Qinghai-Tibet Plateau, which were considered to be caused by underfeeding of the sheep during the harsh winter. The objective of this study was to assess the role of feed supplementation in the milk performance and rumen microbiome of ewes under forage-based diets. Based on parity, milking period, milk yield, and body weight, ten 1.5-yr-old ewes were allocated randomly into two groups. One group of ewes was fed no supplement Control group (CON) and the other group was fed with concentrate feed supplement (Treatment group, T). Individual milk yield was determined daily; both the milk composition and rumen bacterial characteristics were analyzed after the end of feeding trials. RESULTS Results showed that lactose in the milk of the CON group was significantly lower (P < 0.05) than that of the T group at days 30 and 60. Milk yield in the T group was greater than in the CON group at day 30 (P < 0.05). Additionally, the dominant ruminal bacteria (phyla Bacteroidetes, Firmicutes, and Verrucomicrobia) were shared by both groups through 16S rRNA gene pyrosequencing. Greater relative abundance of Bacteroidales RF16 group in family level, Victivallales in order level, Lentisphaeria in class level, and Lachnospiraceae bacterium in species level were observed in the T group than in the CON group (P < 0.05). CONCLUSIONS These results demonstrated that supplementation of concentrate in the cold season improved milk lactose yield and milk production, and the rumen microbial abundance of Tibetan sheep.

Assessing the relationship between the rumen microbiota and feed efficiency in Nellore steers.

BACKGROUND: Ruminants rely upon a complex community of microbes in their rumen to convert host-indigestible feed into nutrients. However, little is known about the association between the rumen microbiota and feed efficiency traits in Nellore (Bos indicus) cattle, a breed of major economic importance to the global beef market. Here, we compare the composition of the bacterial, archaeal and fungal communities in the rumen of Nellore steers with high and low feed efficiency (FE) phenotypes, as measured by residual feed intake (RFI). RESULTS: The Firmicutes to Bacteroidetes ratio was significantly higher (P < 0.05) in positive-RFI steers (p-RFI, low feed efficiency) than in negative-RFI (n-RFI, high feed efficiency) steers. The differences in bacterial composition from steers with high and low FE were mainly associated with members of the families Lachnospiraceae, Ruminococcaceae and Christensenellaceae, as well as the genus Prevotella. Archaeal community richness was lower (P < 0.05) in p-RFI than in n-RFI steers and the genus Methanobrevibacter was either increased or exclusive of p-RFI steers. The fungal genus Buwchfawromyces was more abundant in the rumen solid fraction of n-RFI steers (P < 0.05) and a highly abundant OTU belonging to the genus Piromyces was also increased in the rumen microbiota of high-efficiency steers. However, analysis of rumen fermentation variables and functional predictions indicated similar metabolic outputs for the microbiota of distinct FE groups. CONCLUSIONS: Our results demonstrate that differences in the ruminal microbiota of high and low FE Nellore steers comprise specific taxa from the bacterial, archaeal and fungal communities. Biomarker OTUs belonging to the genus Piromyces were identified in animals showing high feed efficiency, whereas among archaea, Methanobrevibacter was associated with steers classified as p-RFI. The identification of specific RFI-associated microorganisms in Nellore steers could guide further studies targeting the isolation and functional characterization of rumen microbes potentially important for the energy-harvesting efficiency of ruminants.

Differencial rumen protozoa counting from steers fed Napier elephant grass (Pennisetum purpureum Schum) at different maturity stages / Contagens diferenciais de protozoários ciliados em rúmen de bovinos arraçoados com capim elefante Napier (Pennisetum purpureum Schum), em vários estádios de crescimento vegetativo

Napier grass (Pennisetum purpureum Schum) in-3 growing stages: a) 1,30 m tall and 17.54% dry matter; b) 2.35 m tall and 25.84% dry matter: and c) 3,25 m tall and 26.31% dry matter, was fed "ad libitum" to eight rumen fistulated steers all crossbred (5/8 european-zebu) weighting 220 kg, being fed 1,5 kg of a concentrate meal with 24.16% of crude protein. Treatments were compared in a completely randonmized design using the 4th week of each experimental period for rumen liquor sampling for differencial counts of the following protozoa: Entodinium, Diplodinium, Eudipiodinium and Polyplastron. Results showed Entodinium as 96.73% of total protozoa and its concentration per mililiter of rumen fluid decreased linearly as the plant matured (a = 18.2 x 104/ml; b = 12.1 x 104/ml; and c = 9.8 x 104/ml).

Capim elefante Napier (Pennisetum purpureum Schum) colhido em quatro estádios de desenvolvimento: a) 1,30 m de altura e 17,54% de matéria seca; b) 2,35 m de altura e 25,84% de matéria seca; e c) 3,25 m de altura e 26,31% de matéria seca, foi fornecido ad libitum" a 8 bovinos com 5/8 de sangue europeu-zebu, com 220 kg de peso vivo médio, providos de fístulas ruminais. Todos receberam 1,5 kg de uma mistura concentrada com 24,10% de proteína bruta. Os tratamentos foram comparados em um delineamento inteiramente casualizado, sendo que na quarta semana de cada período experimental colheram-se amostras de líquido de rúmen antes da oferta dos alimentos, para contagens diferenciais dos seguintes gêneros de protozoários ciliados e auferir suas concentrações por mililitro: Entodinium spp; Diplodinium spp; Eudiplodinium spp e Polyptastron spp. Os resultados mostraram que os protozoários ciliados do gênero Entodinium predominaram com 96,73% do total da população desses microorganismos. O número de Entodinium spp decresceu com a maturação da planta: a) 18,2 x 104/ml; b) 12,1 x 104/ml; e c) 9,8 x 104/ml.