Search

The study aimed to investigate the effects of two feeding times and two sources of energy supplementation on pH, short-chain fatty acids (SCFA), and in vitro gas production (IVGP) of beef cattle reared in Urochloa brizantha cv. Marandu pastures. We used eight rumen-cannulated ½ Aberdeen Angus x ½ Nellore young bulls (280±7 kg) distributed in a double 4x4 Latin square design. Treatments consisted of supplementation at 0.3% of body weight with corn or citrus pulp, supplied at 0900 or 1700. Ruminal fluid pH was measured with a digital pH analyzer and SCFA was analyzed on a Shimadzu HPLC. The IVGP was determined using a transducer and a data logger for 48 h after incubation of samples combining forage and supplement in real intake proportion (88% forage, 12% supplement). Considering the rapid fermentation of sugars, animals supplemented with pectin maintained higher pH (P = 0.021) due to changes in bacterial populations to digest the pectic substances (Table 1). Lactate production after starch digestion caused lower pH. Despite the differences in evaluated energy substrates, there was no effect on the primary SCFA concentration (P > 0.05). Citrus pulp provided greater formic (P = 0.005) and valeric (P = 0.042) acids concentrations compared with corn, but there was no influence of formic acid in lactic acid production (Table 1). The greater IVGP by citrus pulp (P = 0.0140; Figure 1) may be related to its greater carbohydrate fraction A, soluble with a rapid rate of rumen degradation, and also because its ruminal fermentation results in greater acetic acid production, which provides more ruminal H2 and CO2, favoring the CH4 production. The citrus pulp can be used as an alternative source to corn because it might prevent acidosis, does not affect the main SCFA production, and is a non-human edible feed. [ABSTRACT FROM AUTHOR]

In the present study, we have hypothesized that replacing barley with high proportions of dried citrus pulp in a concentrate-based diet for lambs could increase the intake of unsaturated fatty acids and could reduce the rate of the ruminal biohydrogenation of PUFA, with a consequent improvement of the intramuscular fatty acid composition. To test this hypothesis, 26 Comisana lambs were divided into 3 groups and for 56 d were fed a barley-based concentrate diet (CON; 8 lambs) or 2 diets in which barley was replaced with 24% (CIT24; 9 lambs) or 35% (CIT35; 9 lambs) dried citrus pulp. An overall improvement of the fatty acid composition of LM from lambs fed citrus pulp-containing diets was found. The PUFA/SFA ratio was lower (P < 0.05) in the LM from lambs in the CON group compared with both the CIT24 and CIT35 groups. The thrombogenic index was lower (P < 0.05) in meat from lambs fed the CIT35 diet compared with those fed the CON diet. The CIT35 diet increased the proportion of C20:5 n-3 in the LM (P < 0.05), whereas the CIT24 diet enhanced that of C22:6 n-3 (P < 0.05) compared with the CON diet. Some of these results might be explained considering that feeding the CIT24 and CIT35 diets increased the intake of total fatty acids (P < 0.05) and of C18:3 n-3 (P < 0.01) compared with feeding the CON treatment. On the other hand, phenolic compounds present in citrus pulp could have inhibited the ruminal biohydrogenation of PUFA. This is supported by the fact that regardless of the level of inclusion in the diet, citrus pulp increased the proportion of rumenic acid (P < 0.001) in LM compared with the CON diet. The plasma from lambs fed both CIT24 and CIT35 diets had a greater percentage of vaccenic acid (VA; P < 0.001) compared with that from lambs fed the CON diet, and the CIT35 diet increased the proportion of rumenic acid in plasma compared with the CON treatment (P < 0.05). In the ruminal fluid, stearic acid (SA) tended to decrease, and the sum of CLA tended to increase (P = 0.09) with increasing level of citrus pulp in the diets. Furthermore, the SA/(SA + VA) ratio tended to be lower (P = 0.10) in the ruminal fluid from lambs fed the CIT35 diet compared with that of the CON group. In conclusion, our results support the hypothesis that replacing barley with citrus pulp in the diet of growing lambs improves intramuscular fatty acid composition and underline the need for specific studies to clarify the mechanisms by which feeding citrus pulp affects the fatty acid metabolism in ruminants. [ABSTRACT FROM AUTHOR]

Our objectives were to compare the effects of sources of supplemental N on ruminal fermentation of dried citrus pulp (DCP) and performance of growing steers fed DCP and bahiagrass (Paspalum notatum) hay. In Exp. 1, fermentation of DCP alone was compared with that of isonitrogenous mixtures of DCP and solvent soybean meal (SBM), expeller soybean meal (SoyPLUS; SP), or urea (UR). Ground (1 mm) substrates were incubated in buffered rumen fluid for 24 h, and IVDMD and fermentation gas production kinetics and products were measured. Nitrogen supplementation increased (P < 0.10) ruminally fermentable fractions, IVDMD, pH, and concentrations of NH3 and total VFA, but reduced the rate of gas production (P < 0.10) and the lag phase (P < 0.01). Supplementation with UR vs. the soy-based supplements increased ruminally fermentable fractions (P < 0.05) and concentrations of total VFA (P < 0.10) and NH3 (P < 0.01), but these measures were similar (P > 0.10) between SBM and SP. In Exp. 2, 4 steers (254 kg) were fed bahiagrass hay plus DCP, or hay plus DCP supplemented with CP predominantly from UR, SBM, or SP in a 4 × 4 Latin square design, with four 21-d periods, each with 7 d for DMI and fecal output measurement. Nitrogen-supplemented diets were formulated to be isonitrogenous (11.9% CP), and all diets were formulated to be isocaloric (66% TDN). Intake and digestibility of DM, N, and ADF were improved (P < 0.05) by N supplementation. Compared with UR, the soy-based supplements led to greater (P < 0.05) DM and N intakes and apparent N and ADF digestibilities. Plasma glucose and urea concentrations increased (P < 0.10) with N supplementation and were greater (P < 0.01) for the soy-based supplements than for UR. Intake, digestibility, and plasma metabolite concentrations were similar (P > 0.1) for SBM and SP. In Exp. 3, 24 steers (261 kg) were individually fed bahiagrass hay plus DCP (control), or hay plus DCP supplemented with CP predominantly from UR or SBM. Over 56 d, DMI and ADG were greatest (P < 0.05) in steers fed SBM. Nitrogen supplementation increased (P < 0.05) DMI, ADG, and G:F. However, SBM supplementation produced greater (P < 0.05) DMI and ADG and similar (P > 0.05) G:F compared with UR supplementation. We conclude that supplemental N is important to optimize ruminal function and performance of growing steers fed forage diets supplemented with DCP. Diets with supplemental N mainly from SBM improved diet digestibility and animal performance beyond that achieved by UR. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses effect of source of supplemental nitrogen on the utilization of citrus pulp-based diets by sheep. It mentions that two trials were conducted to examine influence of N enrichment of dried citrus pulp (DCP) through ammoniation versus urea supplementation on digestion and feeding value. It reveals that digestibility of CP-A was lower than that of the other diets supplemented with nonprotein N (NPN).

A variety of feedstuffs of varying carbohydrate composition are available to rectify deficiencies in nutrient supply for growing cattle fed grass silage-based diets. The objective was to examine the effects of replacing rolled barley (starch) with citrus pulp (digestible fiber) in a supplement on intake and performance of young growing cattle offered grass silage ad libitum for 135 days. Weaned, late-maturing breed, steers (n = 34, initial live weight 446 kg, SD 38.0) were blocked by sire breed and weight and from within block randomly assigned to one of three concentrate treatments. The control concentrate, based on rolled barley (starch), comprised of 865 g rolled barley, 60 g soya bean meal, 50 g molasses, and 25 g minerals and vitamins/kg (BAR). In the other two concentrates, barley was replaced with 400 (CIT40) or 800 (CIT80) g/kg (digestible fibre) plus 10 and 20 g soya bean meal, citrus pulp respectively. Concentrates were formulated to have similar concentrations of PDIE (true protein digestible in the small intestine when energy limits microbial protein synthesis) per kg DM (106 g). Steers were individually offered 4.0 kg DM of the respective concentrates, in two feeds daily. Data were statistically analyzed using ANOVA with terms for treatment and block in the model. Supplement type did not affect (P > 0.05) daily grass silage intake (5.05 kg DM). Live weight gain (kg/day) was lower (0.88) and G:F (kg/day) was poorer (10.4) for CIT 80 (P < 0.01) compared to BAR (1.03 and 9.2, respectively) and CIT 40 (1.05 and 8.6, respectively), which did not differ (P > 0.05). Ultrasonically assessed body fat depth or gain did not differ (P > 0.05) between treatments, but muscle depth gain was higher (P < 0.01) for BAR compared to CIT80, with CIT40 being intermediate (P > 0.05). Carcass weight, carcass conformation and fat score, carcass fat depth, kill-out proportion, ultimate pH and temperature of M. longissimus muscle, and drip loss did not differ (P > 0.05) between treatments. Subcutaneous fat lightness ('L' value) was higher (P < 0.01) for CIT80 than BAR, with CIT 40 being intermediate, whereas redness ('a' value) and yellowness ('b' value) did not differ (P > 0.05) between treatments. In conclusion, citrus pulp can replace barley at inclusion rates up to 400g/kg when offered as a supplement to grass silage without negatively affecting performance or selected meat quality traits. [ABSTRACT FROM AUTHOR]