Indigestible cellulose and lignin in determining feces production and apparent digestibility in horses

Four crossbred geldings were used in a randomized blocks experimental design. The objective was to study the use of the internal markers indigestible cellulose (iCEL) and indigestible lignin (iLIG), obtained in situ (cattle) or in vivo (equine) to predict nutrient apparent digestibility in horses. Treatments consisted of different methodologies to determine digestibility: direct method with total feces collection (TC), and indirect method using internal markers iCEL and iLIG obtained either by in situ incubation in bovine rumen or in vivo (IV) using the mobile nylon bag (MNB) technique in horses. Feces production was 2.80 kg in DM, and average recovery rate (p > 0.05) was 101%. Nutrient digestibility coefficient (p > 0.05) estimates were adequately predicted by iCEL and iLIG, obtained in situ or in vivo, with average values of 52.63, 54.17, 64.90, 43.73 and 98.28% for dry matter, organic matter, crude protein, neutral detergent fiber and starch, respectively. It can be concluded that iCEL and iLIG may be obtained in vivo by MNB in horses consuming a forage-concentrate diet, to predict nutrient digestibility coefficients.

Bromatological characteristics and in vitro digestibility of four sugarcane varieties subjected or not to the application of quicklime

The experiment was conducted to evaluate the bromatological characteristics and the in vitro digestibility of four sugarcane varieties, subjected or not to hydrolysis, with quicklime. A completely randomized design was employed with three replications arranged in a 4 × 2 factorial scheme, with four sugarcane varieties (SP 52454, RB 867515, RB 855536 and IAC 862480), hydrolyzed or not. There was significant effect on brix (p < 0.05) and industrial fiber (p < 0.05), and IAC 862480 variety had the lowest levels of industrial fiber. There were no significant difference (p > 0.05) in neutral detergent fiber, acid detergent fiber and lignin levels among the sugarcane varieties under analysis and for the sugarcanes, hydrolyzed or not. The use of sugarcane hydrolysis with 1% quicklime improves the in vitro digestibility of NDF and ADF, regardless of the variety studied. Hydrolysis with 1% quicklime did not alter the sugarcane chemical composition.

Ileal amino acid digestibility in canola meals from yellow- and black-seeded Brassica napus and Brassica juncea fed to growing pigs

Twelve ileal cannulated pigs (30.9 ± 2.7 kg) were used to determine the apparent (AID) and standardized (SID) ileal digestibility of protein and AA in canola meals (CM) derived from black- (BNB) and yellow-seeded (BNY) Brassica napus canola and yellow-seeded Brassica juncea (BJY). The meals were produced using either the conventional pre-press solvent extraction process (regular meal) or a new, vacuum-assisted cold process of meal de-solventization (white flakes) to provide 6 different meals. Six cornstarch-based diets containing 35% canola meal as the sole source of protein in a 3 (variety) × 2 (processing) factorial arrangement were randomly allotted to pigs in a 6 × 7 incomplete Latin square design to have 6 replicates per diet. A 5% casein diet was fed to estimate endogenous AA losses. Canola variety and processing method interacted for the AID of DM (P = 0.048), N (P = 0.010), and all AA (P < 0.05), except for Arg, Lys, Phe, Asp, Glu, and Pro. Canola variety affected or tended to affect the AID of most AA but had no effect on the AID of Lys, Met, Val, Cys, and Pro, whereas processing method had an effect on only Lys and Asp and tended to affect the AID of Thr, Gly and Ser. The effects of canola variety, processing method, and their interaction on the SID values for N and AA followed a similar pattern as for AID values. For the white flakes, SID of N in BJY (74.2%) was lower than in BNY and BNB, whose values averaged 78.5%; however, among the regular meals, BJY had a greater SID value for N than BNY and BNB (variety × processing, P = 0.015). For the white flakes, the SID of Ile (86.4%), Leu (87.6%), Lys (88.9%), Thr (87.6%) and Val (84.2%) in BNB were greater than BNY and BJY. Opposite results were observed for the regular processing, with SID of Lys (84.1%), Met (89.5%), Thr (84.1%), and Val (83.6%) being greater in BJY, followed by BNB and BNY(variety × processing, P < 0.057). The SID of Met was greatest for the white flakes (90.2%) but least for the regular processing (83.0%) in BNY (variety × processing, P < 0.057). It was concluded that the AID and SID of N and AA of the CM tested varied according to canola variety and the processing method used. Overall, the SID values for Ile, Leu, Lys, Met, Thr, and Val averaged across CM types and processing methods were 81.8, 82.6, 83.4, 85.9, 80.8, and 78.4%, respectively.

Effects of flavomycin on ruminal fermentation, In situ degradability and In vivo digestibility in bovine fed sugarcane diets

Problem statement: The aim of the present study was to characterize and differentiate the effects of addition of flavomycin or monensin on ruminal fermentation and degradability as well as on total digestibility in bovine. Approach: Twelve non-pregnant and non-lactating cows (736 kg of BW) were randomly assigned to three treatments: control, flavomycin (20 mg animal-1 day-1) and monensin (300 mg animal-1 day-1). The trial lasted 21 days. The last 10 days were used for external marker administration (15 g of chromic oxide animal-1 day-1). The last 5 days of the trial were used for feces collection and evaluation of corn grain, soybean meal or sugarcane ruminal degradability and the 21st day was used for ruminal fluid sampling. Results: Monensin increased 27.2%, on average, propionate molar proportion at 0, 4, 6, 8, 10 and 12 h after feeding, compared to control and flavomycin groups. When compared to control, flavomycin reduced the degradation rate of soybean meal CP in 31.0%, decreasing the effective degradability when passage rates of 5 and 8% h-1 were used. Dry matter intake, pH, total Short Chain Fatty Acids (tSCFA) or ammoniacal Nitrogen (NH3-N) concentration were not influenced by the addition of either antibiotics. Effective degradability of sugarcane NDF was not influenced by the use of either antibiotic; neither were the TDN nor the digestibility of DM, CP, EE, NFE, ADF, NDF, GE or starch of the diet. Conclusion/Recommendations: In the present study, it was possible to show the beneficial effects of monensin but not of flavomycin, on rumen fermentation