Can a blend of integrated feed additives modulate ruminal fermentation patterns and performance of growing lambs? In vitro and in vivo assessments

Two in vitro and in vivo experiments were accomplished to investigate the impacts of integrated feed additives (IFA, combination of protected fat, lysine, and methionine plus yucca extract, eucalyptus essential oil, and direct-fed microbial) on gas production (GP), ruminal fermentation and degradability parameters and lamb performance, digestibility, and nitrogen balance. In the in vitro experiment, responses of graded doses (0, 25, 50, 75, 100, and 125 g IFA/kg DM) were evaluated. In the in vivo experiment, 15 Barki male lambs (30.43 ± 0.74 kg BW ± SE) were individually allotted in complete randomized design into three treatments (five animal/treatment) as control (basal diet without additive), low dose (50 g/kg DM) and high dose (100 g/kg DM) for 120 days. In vitro results showed that both doses (100 and 125 g/kg DM) quadratically decreased (p < 0.001) GP and ammonia nitrogen (NH-3N) concentration. In vivo experiment revealed that dry matter intake was increased (p = 0.016) with low dose compared to high dose. Inclusion of high dose decreased blood serum glucose concentrations (p > 0.05) and ruminal protozoal populations (p = 0.094) compared with low dose and control diet. Both doses of IFA increased (p < 0.05) serum urea, creatinine, and triglyceride concentrations, while decreased (p < 0.001) ruminal NH3-N concentrations. These results suggested that, although IFA was effective to modify in vitro ruminal fermentation process and feed degradability, such aspects did not improve in vivo performance of growing lambs.

Effect of increasing doses of neem (Azadirachta indica) seed oil on feed intake, nutrients digestibility, ruminal fermentation and nitrogen utilization of Omani sheep

This study was conducted to examine the effects of neem (Azadirachta indica) seed oil (NSO) on feed intake, ruminal fermentability, feed digestibility, nitrogen balance, and blood parameters in Omani sheep. Nine Omani male sheep (BW; 54.44 ± 8 kg/sheep) were used in a replicated 3 × 3 Latin Square design with three dietary treatments and three periods, with each period lasting 21 days. The animals were randomly assigned into three treatment groups: basal diet without NSO (control); 20 mL/sheep per day NSO (low dose) or 40 mL/sheep per day NSO (high dose). Sheep fed with high dose presented lower (p < 0.05) intake, fiber digestibility, and excreted N in urine. However, diet supplemented with high NSO dose had a lower (p < 0.05) ruminal acetate proportion, while increased (p < 0.05) ruminal propionate compared to the control group. Moreover, sheep offered with NSO showed a linear decrease (p = 0.052) in ruminal ammonia nitrogen (NH₃-N) concentration. The high dose increased (p < 0.05) blood glucose and cholesterol, while decreased urea nitrogen concentrations. Emission of predicted methane (CH₄) reduced (p = 0.007) by 13% for high dose compared to the control group. In conclusion, these results suggested that NSO is a potential feed additive with up to 20 ml/kg of DM alters rumen fermentation profile, decreased CH₄ production, feed digestibility, and nitrogen metabolism for sheep.

Influence of Replacement Levels of Orange Waste Silage on Intake, Nutrient Digestion, Ruminal Fermentation and Milk Yield in Barki Goats

Exploring new alternative sources of feedstuffs can contribute to animal production sustainability in some Mediterranean regions in order to overcome the rising food demand. The influence of dietary replacement of wheat straw (WS) with orange waste silage (OWS) on nutrient intakes, apparent digestibility, ruminal fermentation and blood biochemical constituents and milk production of dairy goats were evaluated. Forty pregnant goats (46.30±1.6 kg BW) were housed in individual pens in a completely randomized design and fed (ad libitum) a TMR for 75 days period. Goats were assigned to four experimental diets with the forage amounts consisting of either WS as a control diet (1000 g WS/kg DM in the TMR), a 50:50 mixture of both WS and OWS (500 g WS and 500 g OWS/kg DM in the TMR), an orange waste silage (1000 g OWS/kg DM in the TMR) or corn silage as a positive control (1000 g CS/kg DM in the TMR). The DMI increased linearly (P<0.01), while fiber fractions intake decreased linearly (P<0.01) with increasing of OWS in the diet. Ruminal pH was increased quadratically (P<0.01), whereas NH3-N concentration and total protozoa abundance decreased quadratically (P<0.01) with increasing OWS in the diet. Ruminal acetate content was increased linearly (P = 0.012) by diet; whereas linear effects were observed on propionate and butyrate proportions (P<0.01) as OWS amount increased. Blood urea nitrogen (BUN), non-esterified free fatty acids (NEFA) and β-hydroxybutyrate (BHBA) levels decreased linearly (P<0.01) with ascending amounts of OWS. Serum glucose, BUN, NEFA and BHBA levels were lower (P<0.01) for goats fed the OWS diet than those fed the CS diet. Milk yield and milk nitrogen efficiency were linearly increased (P<0.01), whereas quadratic effects (P = 0.049) were observed on milk urea nitrogen content with increasing dietary OWS. In conclusion, the replacement of WS with OWS enhanced rumen fermentation and milk yield of late pregnant and early lactation Barki goats.

Nutrient digetibility and production responses of lactating dairy cows when saturated free fatty acid supplements are included in diets: A meta-analysis

Our objective was to perform a series of meta-analyses to evaluate the effects of diets supplemented with saturated free fatty acid (FA) supplements (SFAA) compared with nonfat supplemented control diets (CON) on nutrient digestibility and production responses of lactating dairy cows and to determine whether experimental design affects responses to SFFA. We divided SFFA into C16:0-enriched supplements (PALM, FA supplements with ≥80% C16:0) and C16:0+C18:0-enriched supplements (MIX, FA supplements with ≥80% C16:0+C18:0). The database was formed from 32 peer-reviewed publications with SFFA supplemented at ≤3% diet dry matter (DM). We completed 3 different meta-analyses to meet our objectives. We analyzed the interaction between experimental design (continuous vs. change-over) and treatments (CON vs. SFFA; Meta.1). Regardless of experimental design, we evaluated the effect of treatment (CON vs. PALM vs. MIX; Meta.2) and the effect of 1-percentage-unit increase of MIX and PALM in diet DM (Meta.3). In Meta.1, there was no interaction between treatments and experimental design for any variable. In Meta.2, compared with CON, MIX had no effect on NDF digestibility, milk protein yield and energy corrected milk (ECM), increased the yields of milk (1.20 kg/d) and milk fat (0.04 kg/d), and decreased FA digestibility (5.20 percentage units). Compared with CON, PALM increased NDF digestibility (4.50 percentage units), the yields of milk (1.60 kg/d), milk fat (0.10 kg/d), milk protein (0.04 kg/d), and ECM (2.00 kg/d), and had no effect on FA digestibility. Compared with MIX, PALM tended to increase FA digestibility (3.20 percentage units), increased NDF digestibility (3.50 percentage units), milk fat yield (0.06 kg/d), and ECM (1.20 kg/d). In Meta.3, for each 1-percentage-unit increase of supplemental FA in diet DM, MIX had no effect on NDF digestibility, decreased FA digestibility, increased the yields of milk and milk fat, had no effect on milk protein yield, ECM and milk fat content, and decreased milk protein content. For each 1-percentage-unit increase of supplemental FA in diet DM, PALM increased NDF digestibility, had no effect on FA digestibility, increased the yields of milk, milk fat, ECM and milk fat content, tended to increase milk protein yield, and had no effect on milk protein content. Our results indicate no reason for the restrictive use of change-over designs in saturated FA supplementation studies and meta-analyses. Lactating dairy cows responded better to a FA supplement enriched in C16:0 compared with one containing C16:0 and C18:0.

Slow-release urea partially replace soybean in the diet of Holstein dairy cows: intake, blood parameters, nutrients digestibility, energy utilization, and milk production

The present experiment aimed to evaluate the partial replacement of soybean with slow-release urea (Optigen 1200™) in the diet of lactating cows for 84 d. Three-hundred multiparous lactating Holstein (635 ± 25 kg of body weight, BW) cows were stratified by live body weight; parity and previous milk production were randomly assigned into two experimental groups with 150 cows per each treatment. In the control treatment, 25 g soybean meal was replaced by 5.7 g slow-release urea for 84 d. Optigen treatment did not affect feed intake, daily milk production, milk composition, or milk (feed) efficiency; however, increased (P<0.01) total BW gain and daily BW gain. Optigen treatment increased (P<0.01) the digestibility of crude protein and neutral detergent fiber. Optigen treatment increased (P<0.01) estimated N balance, milk urea-N, and net energy (NE) for gain. Without affecting blood total protein, creatinine, urea-N, triglycerides, glucose, β-hydroxybutyrate, or non-esterified free fatty acids, Optigen treatment increased the concentrations of blood albumin and cholesterol compared to the control (P<0.05). In conclusion, slow-release urea could replace soybean meal in ruminant diets with no adverse effects on feed intake, nitrogen utilization, or digestibility; however, improve the total tract digestibility of fiber and crude protein in cows.