Apparent Total Tract Digestibility Of Nutrients Research Articles

Diet supplementation with a mixture of essential oils: Effects on enteric methane emissions, apparent total-tract nutrient digestibility, nitrogen utilization, and lactational performance.

This study examined the effects of supplementing dairy cows with a mixture of essential oils on enteric CH4 emissions, apparent total-tract nutrient digestibility, N utilization, and lactational performance (production, components and efficiency). Thirty-two multiparous lactating Holstein cows were used in a randomized complete block design. Cows averaged (mean ± SD) 95 ± 15.4 DIM, 47.7 ± 4.51 kg milk yield, and 698 ± 68.2 kg BW, at the start of the experiment. The experiment consisted of a 3-wk pretreatment period (i.e., covariate), followed by a 3-wk adaptation to the experimental treatments, and a 10-wk period for data and sample collection. At the beginning of the study, milk yield and DIM data were used to block the cows into 16 blocks of 2 cows each. Subsequently, the blocks were adjusted based on milk yield and enteric CH4 emission data collected during the pretreatment period. Within each block, cows were assigned to 1 of 2 dietary treatments: (1) a basal diet supplemented with a placebo (control, no additive), or (2) a basal diet with the essential oil supplement (Agolin, 1 g/cow/d). The basal diet (i.e., total mixed ration) was composed of 69.3% forage (corn and alfalfa silage and grass hay) and 30.7% concentrate, on a dry matter (DM) basis, while the essential oil mixture consisted mainly of coriander seed oil, eugenol, geraniol and geranyl acetate. Twice daily, the essential oil supplement was thoroughly mixed with 50 g of a commercial protein supplement (i.e., carrier) and 500 g of the TMR and this premix (i.e., 550 g/meal) was offered to the cow before the basal diet. No interactions between the essential oil supplement and the sampling week were observed for any of the response variables. Dry matter intake, apparent total-tract nutrient digestibility and N balance were unaffected by feeding the essential oil supplement. Yields of milk, 4% FCM, and ECM were not modified by the experimental treatment. Neither feed efficiency (kg milk/kg DMI, kg 4% FCM/kg DMI, kg ECM/kg DMI) nor dietary N use efficiency in milk N secretion (i.e., g milk N/ g N intake) were affected by essential oil supplementation. Body weight change and BCS did not differ between cows fed the essential oil supplement versus cows fed the control. Daily enteric CH4 emissions, CH4 yield, and CH4 intensity averaged 498 g/d, 18.4 g/kg of DMI, and 11.0 g/kg of ECM, respectively, and were unchanged by essential oil supplementation. We conclude that supplementing cows fed a high-forage diet with 1 g/d of this essential oil mixture did not positively affect lactational performance, nutrient digestibility, and N utilization, or reduce enteric CH4 (emissions, yield, and intensity). More research is needed to identify the optimal dose of this essential oil mixture and elucidate how it may interact with the basal diet to improve the mixture's efficacy.

Effects of supplementation with 1,25(OH)2D3-glycoside of herbal origin in the diet of nursery piglets

Context To provide adequate dietary vitamin D in nursery piglets, 1,25(OH)2D3-glycoside could be a potential alternative to supplements currently in use. Aims The effect of this supplement on apparent total tract nutrient digestibility, growth performance, health status, and bone traits was assessed in nursery piglets. Methods Digestibility was assessed in 30 piglets (23.8 ± 3.32 kg), and growth performance in 135 weaned piglets (8.0 ± 0.53 kg). Both trials used randomized complete block designs based on bodyweight, with five treatments: −D3: no vitamin D supplementation; +D3: 100% of the vitamin D requirement supplied as cholecalciferol; and +D3 + 0.5, 1.0, or 1.5 μg of 1,25(OH)2D3-glycoside. Key results From Day 21 to 35, piglets fed D3 + 1.0 diet showed greater average daily gain compared to −D3 or D3 + 1.5, and a greater average daily feed intake was observed in piglets fed +D3, D3 + 0.5, and D3 + 1.0 compared to −D3 or D3 + 1.5. From Day 0 to 7, diarrhoea prevalence was lower in piglets fed D3 + 1.0 compared to −D3, D3 + 0.5, and D3 + 1.5. Across the entire period, animals fed D3 + 1.0 had lower diarrhoea prevalence compared to D3 + 0.5. Serum 25(OH)D3 concentrations was lowest in −D3 piglets. Leukocyte concentrations were greater in piglets on D3 + 1.0 than with D3 + 1.5, whereas eosinophil concentrations were lowest in piglets fed D3 + 0.5. Alkaline phosphatase activity was higher in piglets on +D3 than with D3 + 0.5 or D3 + 1.5. The greatest and lowest bone Ca contents were observed in treatments D3 + 1.5 and D3 + 0.5, respectively. The bone magnesium contents was lowest in piglets fed -D3. Conclusions Adding 1,25(OH)2D3-glycoside to diets containing adequate vitamin D contents as cholecalciferol did not increase serum 25(OH)D3 concentrations, but physiological and metabolic parameters were improved and, in general, 1.0 μg of 1,25(OH)2D3-glycoside showed the best effects on performance, serum vitamin D, health status, and bone traits. Implications This research has provided new information on the effects of 1,25(OH)2D3-glycoside supplementation in diets for nursery piglets and has shown its potential use for bolstering general health.

Effects of calcium and buffer sources on lactational performance, ruminal fermentation, nutrient digestibility, and metabolism of dairy cows

The objective was to investigate the effects of calcium and rumen buffer sources on lactational performance, ruminal fermentation, enteric gas emissions, apparent total-tract digestibility of nutrients, and blood variables of lactating dairy cows. A replicated 3 × 3 Latin square design experiment was conducted with 9 primi- and 9 multiparous mid-lactation Holstein cows. Cows were fed the same basal diet, except for the inclusion (as % DMI) of the following minerals: (1) CON, 0.80% limestone and 0.55% NaCl; (2) BICARB, 0.80% limestone and 0.80% NaHCO3; and (3) ARAG, 0.80% aragonite and 0.55% NaCl. Dry matter intake was decreased by ARAG compared with CON but not with BICARB. Treatments did not affect milk yield, ECM, or yields of milk components. Feed efficiency was increased by BICARB compared with CON but not with ARAG (i.e., 1.72, 1.64, and 1.70, respectively). Compared with CON, milk fat was increased by both BICARB and ARAG (3.32% vs. 3.58%, respectively). Milk protein concentration tended to be slightly decreased (i.e., 2%) by ARAG compared with CON but not with BICARB. Milk total solids and MUN concentrations were increased by BICARB and tended to be increased by ARAG, compared with CON. Treatments did not affect ruminal fermentation variables, except that ARAG increased butyrate molar proportion, compared with CON but not with BICARB. Additionally, ruminal NH3 concentration was greater for ARAG than for BICARB. Enteric gas emission and apparent total-tract digestibility of nutrients were not affected by treatments in the current study. Blood pH was not affected by treatments, and blood ionized Ca concentration was greater for ARAG than for BICARB, but neither was different from CON. Treatments did not affect plasma haptoglobin, β-hydroxybutyrate, or urea N concentrations. Overall, rumen buffering capacity of ARAG appears to be similar to that of BICARB, which was supported by increased milk fat, compared with CON. Compared with BICARB, ARAG increased ionized Ca concentration because of decreased base excess and HCO3- concentrations in blood.

Performance, nutrient digestibilities, and metabolic profiles of Holstein calves fed whole milk or milk replacer at two feeding levels.

The macronutrient composition of common milk replacers (MR) largely differs from bovine whole milk (WM). These differences are more nutritionally relevant when calves receive higher milk allowances. Therefore, the present study compared fresh WM with a conventional MR fed at 2 level of feeding allowances evaluating growth performance, apparent total-tract nutrient digestibilities, nitrogen (N) balance, and serum metabolite profiles in calves. Forty-eight newborn Holstein male calves (1.96 ± 0.99 d of age; 45.0 ± 4.37 kg BW) were blocked by arrival date and age. Calves in each block were then randomly assigned to the 4 treatments (n = 12/treatment): MR or WM at a high (9.0 L/d) or low feeding allowance (4.5 L/d) fed 3 times daily. Calves were weaned between wk 6 and 10 following the introduction of the starter feed in wk 6. The study ended 13 wk after the arrival at the facility. Blood and body weights were collected on arrival, and weekly thereafter. Total 24h-collection periods of feces and urine was performed at wk 2, 4, 5, 7, 9, 11, and 13. Remarkably, no interactions were observed between liquid feed and level of supply. Calves fed MR had higher ADG during the pre-weaning phase than to calves fed WM. However, calves fed WM had an increased growth rate post-weaning, resulting in no difference in BW at the end of the study. Calves fed WM had a higher apparent crude fat digestibility during the weaning period. Metabolic N efficiency, expressed as N balance relative to digestible N supply, was higher during the pre-weaning phase, but tended to be lower during the post-weaning phase for calves fed MR as compared with calves fed WM. In the pre-weaning period, serum glucose, BHB, nonesterified fatty acids (NEFA), total protein (TP), urea, albumin, globulin, triglyceride (TG), and cholesterol were influenced by liquid feed source. Carry-over effects of milk source on TG and TP were observed during the post-weaning period. As expected, calves fed a high-milk allowance showed better ADG at pre-weaning and were consistently heavier throughout the study than calves fed a low-milk allowance. Feeding a high-milk allowance did not negatively affect nutrient digestibility during the post-weaning phase. In the pre-weaning phase, milk allowance affected glucose and cholesterol metabolism, whereas TG, TP, albumin, and NEFA concentrations were affected during the post-weaning period. From a single oral dose of indigestible markers (Cr-EDTA, lactulose, and D-mannitol), calves fed a high-milk allowance showed greater urinary recovery of all markers after 6h of collection, but not after 24h. Calves fed a high-milk allowance had a higher proportion of days with lower fecal scores during the pre-weaning phase. In conclusion, the serum metabolite profiles of calves throughout the study were highly influenced by milk source. Higher milk allowance increased growth performance and had no adverse effects on starter feed intake or nutrient digestibility in the post-weaning phase. The multiple effects described for milk source and level of supply were overall independent, presenting no relevant interactions.

Increasing the level of hemicelluloses in the lactation diet affects the faecal microbiota of sows and their piglets without affecting their performances

BackgroundSpecific sources of dietary fibres in sow gestation and lactation diets, such as inulin or wheat bran, have been shown to affect both the sow and its litter health by modulating the piglet’s intestinal microbial population and composition. However, only a few studies have reported the effects of some specific fractions of the cell wall of the plants in the sow’s lactation diet. Therefore, this study investigates the effect of increasing the level of HCs in a sow’s lactation diet on the nutrient apparent total tract digestibility (ATTD), the faecal volatile fatty acid (VFA) profile, the microbiota of the sow and the microbiota and the performances of slow-growing (SG) and fast-growing (FG) piglets.ResultsIncreasing HCs level increased (P < 0.05) the proportions of butyrate and valerate on day 3, and the ATTD of acid detergent fibres (ADF), neutral detergent fibres (NDF), and gross energy and decreased (P < 0.05) the proportion of propionate on day 17, and the ATTD of crude protein. The beta diversity was affected (r2 = 0.11; P = 0.02) by the maternal dietary treatments with 11 common genera differing (P < 0.05) in the sow’s faecal microbiota, and five in the piglet’s microbiota. Regardless of the maternal dietary treatment, SG piglets had a lower (P < 0.05) proportion of isobutyrate and isovalerate, a lower (P < 0.05) abundance of Lachnospiraceae_XPB1014_group, Enterococcus, and Succinovibrio genera, and a greater (P < 0.05) abundance of Olsenella than FG piglets.ConclusionsIncreased HCs level in a sow’s lactation diet affects the ATTD of nutrients, the faecal VFA and microbiota profiles of the sows with limited effects on SG and FG piglets’ faecal microbiota and no effects on the performance or VFA profile of these piglets.

249 Effects of sorghum silage kernel processing on growth performance and blood metabolites of beef heifers

Abstract Our previous studies suggested that using a shredlage (SHRD) processor or a conventional (CONV) sorghum kernel processor leads to similar apparent total tract nutrient digestibility of whole plant sorghum silage (WPSS). This study evaluated the effects of feeding WPSS harvested using different kernel processors (CONV vs. SHRD), on growth performance of beef heifers. Grain sorghum (ADV2450IG; Advanta Seeds, Argentina) was harvested at the hard-dough stage with a Class Jaguar 950 (Harsewinkel, Germany), switching the kernel processor to generate the forage material for the two treatments: CONV and SHRD. The material was bagged in two 2.7 m diameter bags and allowed to ferment for 3 mo. Black Angus heifers [n = 96; body weight (BW) = 15 ± 1 mo, 249.6 ± 28.6 kg] were blocked by initial BW, and randomly assigned to pens (8 heifers/pen, 6 pens/treatment). Diets consisted, all in DM basis, of WPSS of each respective type (SHRD or CONV) at 90.5%, expeller soybean meal at 7.0%, and a vitamin-mineral-NNP concentrate at 2.5%. The experiment consisted of a 14-d adaptation period, followed by a 56-d growing period; and feed was offered once daily. Data were analyzed as a randomized complete block design, using pen as the experimental unit, with the fixed effect of treatment and the random effect of block. No differences were observed (P &amp;gt; 0.10) for final BW, dry matter intake, and residual feed intake. However, CONV fed heifers tended to gain more BW per day (ADG, 0.83 vs. 0.77 kg/d; P = 0.07) and had greater gain to feed ratio (GF, 0.083 vs. 0.075 kg/kg; P = 0.05) and greater Kleiber ratio (KR, 12.1 vs 11.2 g/kg; P = 0.05) as compared with SHRD fed heifers. Furthermore, performance calculated dietary Net Energy of gain (NEg) in CONV fed heifers tended to be greater than that for SHRD (0.70 vs. 0.65 Mcal/kg of diet DM, respectively; P = 0.06). Moreover, blood serum from CONV fed heifers had 16% greater total bilirubin (P = 0.04), 12% greater cholesterol (P = 0.02), and slightly greater non esterified fatty acids (P = 0.03) concentrations. Noteworthy, serum concentrations of total bilirubin were correlated (P ≤ 0.03) with ADG, GF, KR and NEg. In conclusion, the type of kernel processor utilized for the harvest of sorghum silage may have an impact on feed efficiency of beef cattle. These differences could be related to changes on the site of utilization of nutrients, particularly starch; what could also explain the differences on blood metabolites. However, further research is needed to help explain these findings.

Prolonged feeding of high-concentrate diet remodels the hindgut microbiome and modulates nutrient degradation in the rumen and the total gastrointestinal tract of cows

The aims of this research were to evaluate how prolonged feeding of a high-concentrate diet affects the ruminal degradation kinetics of fiber and starch, and to evaluate the effects of the high-concentrate diet on apparent total-tract nutrient digestibility in dairy cows. We also investigated the dysbiotic effects and the remodeling of the hindgut microbiome with prolonged high-concentrate feeding. Nine Holstein cows were used in 2 experimental periods; in each period, cows were first fed a 100% forage diet for 1 wk, followed by stepwise adaptation during one week to a high-concentrate (HC) diet (65% concentrate), which was then fed for 4 consecutive weeks. The kinetics of in situ ruminal degradability of grass silage (DM and NDF), corn grain and wheat grain (DM and starch), as well as the apparent total-tract nutrient digestibility were evaluated in the forage feeding and in wk 4 on the HC diet. Whereas the hindgut microbiome and fermentation profile were evaluated on a weekly basis. Regarding the in situ ruminal degradability due to grain type, the rate of degradation of the potentially degradable fraction and the effective rumen degradability of wheat grain were greater compared with corn grain. The in situ ruminal degradability of NDF decreased with the HC diet. However, the apparent total-tract digestibility of CP, fat, starch, NDF, ADF, and NFC increased with the HC diet compared with forage feeding. In addition, the HC diet increased the concentration of short-chain fatty acids in the hindgut, lowering fecal pH by 0.6 units, which correlated positively with microbial α diversity. This resulted in lower α diversity with the HC diet; however, α diversity (number of amplicon sequence variants) showed recovery in wk 3 and 4 on HC; in addition, microbial β diversity did not change from wk 2 onward on the HC diet. Two microbial enterotypes were identified: one for the forage diet with abundance of Akkermansia and Anaerosporobacter, and another enterotype for the HC diet with enrichment in Bifidobacterium and Butyrivibrio. Overall, results show that major microbial shifts and hindgut dysbiosis occurred in wk 1 on the HC diet. However, the hindgut microbial diversity of cows adapted after 3 wk of consuming the starch-rich ration. Thus, feeding the HC diet impaired fiber degradation in the rumen, but increased apparent total-tract nutrient digestibility. Likely, the forage diet contained less digestible NDF than the HC diet due to greater inclusion of forages with lower NDF digestibility and lower inclusion of more digestible nonforage NDF. Results also suggest that the adaptation of the hindgut microbial diversity of cows observed 3 weeks after the diet transition likely contributed to enhance total-tract nutrient digestibility.

Effects of feeding sulfate trace minerals above recommendations on nutrient digestibility, rumen fermentation, lactational performance, and trace mineral excretion in dairy cows

Most trace minerals (TM) are fed above dairy cow requirements in commercial herds but their fate and effects on dairy cows have not been well documented. In this study, we evaluated the effects of feeding short-term sulfate TM above recommendations on apparent total-tract digestibility of nutrients, rumen fermentation characteristics, serum concentrations, milk yield and composition as well as milk, fecal, and urinary TM excretion in mid-lactation dairy cows. Eight multiparous Holstein cows [average body weight: 684 (SD: 29) kg at 82 (SD: 10) days in milk] in a quadruple 2 × 2 crossover design were fed a basal diet, differing in sulfate TM supplement concentrations, to provide either 0.11, 17, and 63 (control; CON) or 0.95, 114, and 123 (high trace minerals; HTM) mg of dietary Co, Mn, and Zn/kg of dry matter, respectively. Each experimental period had a 21-d adaptation to the diet, followed by a 10-d sample collection period. Feed ingredients and total feces and urine were collected during 4 consecutive d and rumen fluid was collected 0, 1, 2, 4, and 6 h relative to feeding. Milk yield was recorded daily and milk samples were collected on 4 consecutive milkings. Ingestion of Co, Mn, and Zn was higher for HTM compared with CON group by 216, 233, and 93%, respectively. Dry matter intake averaged 25.0 (SE = 0.6) kg/d, and apparent total-tract digestibility of major nutrients was similar between treatments. There was no measurable effect of HTM on ruminal pH, major volatile fatty acids, and protozoa counts. Isovalerate molar proportion was 9.4% greater for HTM compared with CON group. Neither milk yield (43.5 kg/d; SE = 0.8) nor milk fat and protein concentrations differed between treatments. Milk urea nitrogen concentration was significantly higher for HTM (11.7 mg/dL) compared with CON group (9.7 mg/dL; SE = 0.7). Fecal excretion of Co, Mn, and Zn increased by 223, 198, and 75%, respectively, for HTM compared with CON group. Urinary excretions of TM were marginal compared with feces, and only urinary Co and Mn were significantly higher for HTM than CON cows as similarly obtained for serum Co and Mn concentrations. Milk TM yields were not modified by treatments. In summary, short-term dietary sulfate TM supply over the recommendation did not improve cow performance but significantly increased fecal TM excretion, which could have impacts on TM accumulation in soils where manure is applied and could potentially result in leaching into nearby watersheds. Further studies are needed to evaluate the impact of high fecal TM excretion on the environment using the One Health approach. Moreover, the impacts of TM oversupply on milk production and cow health should be evaluated by long-term experiments.

Effects of quebracho–chestnut tannin extract supplementation on production performance, nitrogen partitioning, and rumen fermentation patterns in early-lactating Holstein cows

Tannins have been extensively studied to decrease nitrogen excretion, however, the effects of tannins on animal production were inconsistent. The objective was to evaluate the effects of a mixture of quebracho-chestnut tannin extract (QCTE) supplementation on the production performance, nutrient digestibility, rumen fermentation patterns, and N partitioning in dairy cows. Sixty multiparous Holstein cows (mean ± standard deviation; average 717 ± 51 kg of body weight, 2.5 ± 0.2 of parity, 47 ± 1.9 kg/d of milk production, 78 ± 3.2 d of days in milk were randomly divided into four groups. Cows in different groups were provided QCTE at doses of 0, 10, 20, and 30 g/d per cow for 56 d. Although QCTE supplementation did not affect dry matter intake (DMI) and total-tract apparent digestibility of nutrients, milk yield and milk protein yield increased linearly (P = 0.01), and a trend for a linear (P = 0.07) increase in milk/DMI were observed with increasing QCTE supplementation. Increasing QCTE supplementation decreased the milk urea-N concentration and somatic cell count linearly (P < 0.05), tended to linearly (P < 0.1) decrease the concentration of blood urea-N and ruminal ammonia nitrogen, linearly (P < 0.05) increased levels of total antioxidant capacity and superoxide dismutase, and the molar proportions of ruminal propionate. Additionally, total N excretion was not affected by QCTE treatments, but QCTE supplementation linearly (P = 0.04) increased N utilization efficiency and tended to linearly (P = 0.1) decrease urea-N excretion in the urine. In conclusion, feeding QCTE at a dose of 30 g/d per head to cows in early lactation could increase antioxidant enzyme activities, improve production performance, and decrease environmentally labile urinary N excretion under the conditions of the study.

Effect of nicotinic acid supplementation on digestion, metabolism, microbiome, and production in late-lactation Holstein cows

The purpose of this experiment was to determine if nicotinic acid (NA) effects on dairy cows and rumen microbial characteristics are forage type dependent (corn silage, CS; grass silage, GS). Four late lactation (days in milk = 225 +/- 12 d) Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. The main effects were a CS (66.10% CS) based diet or a GS (79.59%) based diet with or without 12 g/d NA. Each experimental period lasted for 28 d. Milk production and milk components, blood metabolites, apparent total-tract nutrient digestibilities, minutes rumen pH were below 5.8 as an indicator of ruminal acidosis, and body temperature changes were analyzed as indicators of heat stress. Nicotinic acid supplementation did not improve apparent total-tract nutrient digestibility. Feeding a GS-based diet improved NDF and hemicellulose digestibility. Feeding a CS-based diet increased the apparent total-tract digestibility of fat, and minutes rumen pH below 5.8 for a greater proportion of the time. The CS-based diet also improved milk yield, milk fat and protein yields, and energy-corrected milk yield; however, somatic cell count and BHB were also increased. Supplementing NA tended to decrease nonesterified fatty acids, especially when combined with GS where DMI was low. There was a trend for the total protozoa population to increase when GS and NA were fed but decreased when CS and NA were fed. Nicotinic acid tended to decrease rumen protozoal populations of Dasytricha, but increased populations of Ophryoscolex and Diplodiniinae with GS diets and decreased with CS diets. Entodiniinae were increased with CS but NA had no effect. Body temperature was increased when a CS-based diet was fed when compared with a GS-based diet. More research is needed to determine how NA can affect rumen microbial protein synthesis and what kind of diets will provide the optimum effect.

Asparagopsis taxiformis inclusion in grass silage-based diets fed to Norwegian red dairy cows: Effects on ruminal fermentation, milk yield, and enteric methane emission

Efforts to mitigate enteric methane (CH4) emission from ruminants by using the red macroalgae Asparagopsis taxiformis (AT) have demonstrated promising results both in vitro and in vivo. We assessed the effects of wild harvested and freeze-dried AT inclusion in the grass silage-based diets of Norwegian Red dairy cows on feed intake, milk yield and composition, rumen fermentation and CH4 emission. Fifteen (9 rumen cannulated and 6 intact) multiparous cows with an average (±SD) covariate period milk yield (MY) of 33.0 (3.8) kg/day were used in the experiment. The cows were divided into three groups (n = 5) after blocking for cannulation, and initial MY. After feeding on a common diet for 21 days (i.e., Covariate period), the groups were randomly allocated to three treatments: Control (no seaweed), 0.125%AT (Control + 0.125%AT, on organic matter (OM) basis) and 0.25%AT (Control + 0.25%AT, on OM basis). The cows were adapted to their diets for 13 days, followed by 39 experimental days for data collection. Inclusion of AT at 0.125% level did not affect dry matter intake (DMI, kg/d) but signicantly reduced both MY and energy corrected milk yield (ECM, kg/d) (P < 0.05) with a tendency for lower CH4 production (g/d) relative to the control group. Dry matter intake, ECM and CH4 production were reduced (P < 0.05) by 0.25%AT inclusion relative to the Control group. Apparent total tract nutrient digestibility (%), ECM per kg DMI, CH4 yield (g CH4/kg DMI) and CH4 intensity (g CH4/kg ECM) were not affected by AT inclusion. Inclusion of AT, at both levels, significantly reduced (P < 0.05) ruminal fluid total short chain fatty acids and molar proportions of actate, while increasing (P < 0.05) the molar proportion of propionate and isovalerate. Inclusion of AT decreased contents (%) of milk fat (P = 0.018) and protein (P = 0.010) resulting in significanly lower fat and protein yields. Lactose content (%) was higher for the AT groups (P = 0.021) but this did not compensate for lower MY resulting in lower milk lactose yield. Milk iodine content increased in a dose dependent manner with AT inclusion. In conclusion, AT inclusion at 0.25% level reduced CH4 emission from dairy cows with a grass silage-based diets. However, the reduced DMI for the 0.25%AT group along with reduced MY and elevated milk iodine content for both AT groups, for this particular harvest of AT, would suggest possible constraints for large scale inclusion of AT in dairy cow production.

Black soldier fly larvae meal in an extruded food: effects on nutritional quality and health parameters in healthy adult cats

Abstract We aimed to evaluate the effects of including black soldier fly larvae meal (BSFL) meal in a dry extruded food on nutritional quality and some health aspects in healthy adult cats. Two dry extruded foods with either poultry meal (control) or 37.5% BSFL meal were fed to eight (3.8-5.2 kg BW; 2.3-y.o.) cats in a cross-over design with two 28-day periods. Food acceptance was recorded throughout the study and samples were collected during the last 7 days of each period for assessment of apparent total tract nutrient digestibility, faecal consistency, fermentation products and microbiota, and blood biochemistry and haematology. Foods were well-accepted and faeces were well-formed with optimal consistency scores. Digestibility values for dry matter, organic matter, nitrogen and gross energy were considered high for the BSFL meal-based food but lower than for the control food (). Unexpectedly, inclusion of BSFL meal had a profound impact on the intestinal microbial activity and composition as illustrated by increased faecal short-chain fatty acids () and biogenic amines concentrations () and reduced bacterial diversity () and shifts in multiple genera (e.g. more Bifidobacterium) in the faeces (). Minor changes in haematology and serum biochemistry parameters were found and deemed not clinically relevant. Overall, this study showed that a BSFL meal-based extruded dry food is readily accepted by healthy adult cats, yields optimal faecal consistency, had suitable nutrient digestibilities and can support their health when fed for 28 days with new leads for impact on feline gut health.

Feeding live or inactive yeast to primiparous Jersey cows: nutrient digestibility, rumen fermentation, and milk fatty acid profile

ABSTRACT The aim of this study was to evaluate the effects of live yeast (LY) or inactive yeast (IY) on intake and apparent total-tract digestibility of nutrients, ruminal fermentation, milk yield and composition, milk fatty acid profile, N utilisation, and microbial protein synthesis of primiparous Jersey cows. Twelve primiparous Jersey cows were employed, with an average body weight of 403 kg, a lactation period of 100 days, and average daily milk output of 14.7 kg. The experimental diets were: 1 – CON (no additives); 2 – LY (inclusion of 40 g/day of live yeast); 3 – IY (inclusion of 40 g/day of inactivated yeast wall). Cows fed LY exhibited the greatest DM intake. Cows’ intake IY had the greatest digestibility of DM, OM, and NDF. Feeding IY reduced ruminal concentrations of acetate, isobutyrate, and branched-chain fatty acids. Cows fed either LY or IY increased the production of milk and FCM. Cows under the LY treatment had greater milk fat content. Cows fed LY had the greatest N intake. Yeast treatments also increased the absorbable purine estimation. Supplementing primiparous dairy cows with yeast products, especially live yeast, improved dry matter intake by positively influencing digestibility, particularly for starch and NDF.

Dietary supplementation with live or autolyzed yeast: Effects on performance, nutrient digestibility, and ruminal fermentation in dairy cows

This study was conducted to evaluate the effects of live or autolyzed yeast supplementation on dairy cow performance and ruminal fermentation. Two experiments were conducted to evaluate performance, feed sorting, total-tract apparent digestibility of nutrients, purine derivatives excretion, N utilization, ruminal fermentation, and abundance of specific bacterial groups in the rumen. In Exp. 1, 39 Holstein cows (171 ± 40 d in milk and 32.6 ± 5.4 kg/d milk yield) were blocked according to parity, days in milk, and milk yield and randomly assigned to the following treatments: Control (CON); autolyzed yeast (AY) fed at 0.625 g/kg DM (Levabon, dsm-firmenich); or live yeast (LY) fed at 0.125 g/kg DM (Vistacell, AB Vista). Cows were submitted to a 2-wk adaptation period followed by a 9-wk trial. In Exp. 2, 8 ruminal cannulated Holstein cows (28.4 ± 4.0 kg/d milk yield and 216 ± 30 d in milk), of which 4 multiparous and 4 primiparous, were blocked according to parity and enrolled into a 4 × 4 Latin square experiment with 21 d-periods (the last 7 d for sampling). Cows within block were randomly assigned to treatments sequences: control (CON2); live yeast (LY) using the same product and dietary concentration as described in Exp. 1; or autolyzed yeast fed at 0.625 g/kg DM (AY) or 0.834 g/kg DM (AY2). In Exp. 1 and 2, nutrient intake and total-tract apparent digestibility were not affected by treatments. Sorting for long feed particles (>19 mm) tended to be greater in cows fed yeast supplements than CON in Exp.1. Efficiency of N conversion into milk N was increased when feeding yeast supplements in Exp. 1. 3.5% Fat-corrected milk yield tended to be greater in cows fed yeast supplements than CON. Feed efficiency was increased when yeast supplements were fed to cows in relation to CON in Exp. 1. In Exp. 2, yield of fat-corrected milk and fat were greater in cows fed yeast supplements compared with CON2. Uric acid concentration and output in urine were increased when feeding yeast supplements when compared with CON2. Neither ruminal pH nor total volatile fatty acids were influenced by treatments. The current study did not reveal treatment differences in ruminal abundance of Anaerovibrio lipolytica, genus Butyrivibrio, Fibrobacter succinogenes, Butyrivibrio proteoclasticus, or Streptococcus bovis. Yeast supplementation can increase feed efficiency without affecting nutrient intake and digestibility, ruminal volatile fatty acid concentration, or ruminal abundance of specific bacterial groups. Supplementing live or autolyzed yeast, regardless of the dose, resulted in similar performance.

Effects of increasing dose of a hybrid bacterial 6-phytase on apparent total tract nutrient digestibility, release of free myoinositol, and retention of calcium and phosphorus, and growth performance of pigs

The objective of this study was to investigate the effects of increasing doses of a hybrid bacterial 6-phytase on apparent total tract digestibility (ATTD) of energy and nutrients, plasma level of free myoinositol, retention of calcium (Ca) and phosphorus (P), and growth performance of growing pigs fed Ca and P deficient diets. A total of 15 barrows [21.5 ± 1.4 kg BW; Duroc × (Landrace × Yorkshire)] were allotted to a triplicated 5 × 5 Latin square design with 5 dietary treatments and 5 periods per each square. Pigs were individually housed in a metabolism crate. Five dietary treatments consisted of 5 levels of phytase (0, 500, 1000, 1500, and 2000 FTU/kg) supplemented to a basal diet containing nutrients meeting the requirement except for Ca and P. The basal diet was deficient in total Ca and P by 2.2 and 1.7 g/kg below the recommendations from NRC, respectively. Data were analyzed using orthogonal polynomial contrasts using Proc MIXED of SAS and the optimal phytase levels were determined by a broken line analysis using Proc NLMIXED. Increasing phytase supplementation increased (linear: P < 0.01; quadratic: P < 0.01) ATTD of Ca and P and retention of Ca and P. Increasing phytase supplementation increased (linear: P < 0.05; quadratic: P < 0.05) myoinositol contents in plasma. Based on broken line analyses, ATTD of Ca and retention of Ca were increased until phytase supplementation were increased from 0 to 668 ± 65 FTU/kg (P < 0.01) and 0 to 668 ± 69 FTU/kg (P < 0.01), respectively. The ATTD of P and retention of P were increased until phytase supplementation contents were increased from 0 to 780 ± 86 FTU/kg (P < 0.01) and 0 to 773 ± 93 FTU/kg (P < 0.01), respectively. Myoinositol contents in plasma were increased (11.4 to 22.8 µmol/L) until phytase supplementation were increased from 0 to 705 ± 212 FTU/kg (P < 0.05). Increasing phytase supplementation linearly increased (P < 0.05) average daily gain and tended to linearly increase (P = 0.053) gain to feed ratio. In conclusion, supplementation of a hybrid bacterial 6-phytase improved ATTD of Ca and P, retention of Ca and P, complete hydrolysis of phytate, and growth performance of pigs compared with pigs fed a Ca and P deficient basal diet. Supplementation of a hybrid bacterial 6-phytase at a range of 650 to 800 FTU/kg feeds provided the optimal improvement of Ca, P, and phytate utilization.

Duckweed protein as an alternative plant-based protein source for dog and cat dry diets.

Duckweed has attracted increasing attention as a high-quality and sustainable novel plant-based protein source. However, little research has been conducted in dogs and cats. We evaluated the effects of inclusion of duckweed protein (Lemna; MCSelect; Parabel; Vero Beach, FL) primarily in replacement of pea protein in dog diets at 0%, 5%, and 10% and cat diets at %, 10%, and 15% on stool quality, nutrient digestibility, and palatability. We hypothesized that duckweed protein would be a viable protein source in both dog and cat diets by showing no detriment to nutritional outcomes. All feeding tests were conducted at an independent research facility (Susquehanna, PA). A standard 2-bowl palatability test over a 2-d period was conducted with adult animals (n = 30 each) to determine intake ratio between test diets (duckweed-containing diets) and control diets (0% duckweed protein). Apparent total tract nutrient digestibility was conducted with 18 adult dogs and 21 adult cats (n = 6 to 7 per diet) with 5 d of diet acclimation followed by 5 d of total fecal collection. Stool quality was evaluated on a 1 to 5 scale where 1 = non-formed or diarrhea and 5 = hard, formed. Palatability data were analyzed using paired t-test (daily consumption) and chi-square test (first choice). All other data were analyzed by ANOVA and contrast (SAS version 9.4). For cats, 10% duckweed had greater (P < 0.05) palatability than control, while no difference was observed between 15% duckweed protein and control. For dogs, 5% and 10% duckweed protein had (P < 0.05) lower palatability, demonstrating a preference to control. Both cats and dogs fed duckweed diets had acceptable stool quality (Mean = 3.4 and 3.3, respectively). No detriments in nutrient digestibility were observed in dogs fed 5% and 10% duckweed protein; however, cats fed 10% and 15% duckweed protein had (P < 0.05) lower dry matter, protein, and energy digestibility vs. control. In conclusion, the data collected indicate that duckweed can be a viable replacement for other plant-based proteins in dog diets at inclusion levels up to 10%; more development is needed for duckweed protein inclusion into cat diets.

Effects of betaine on growth performance and intestinal health of rabbits fed different digestible energy diets.

An experiment was conducted to determine the effects of betaine on growth performance and intestinal health in rabbits fed diets with different levels of digestible energy. During a 36-d experiment, a total of 144 healthy 35-d-old weaned New Zealand white rabbits with a similar initial body weight (771.05 ± 41.79g) were randomly distributed to a 2 × 3 factorial arrangement. Experimental treatments consisted of two levels of digestible energy (normal: 10.20 and low: 9.60MJ/kg) and three levels of betaine (0, 500, and 1,000mg/kg). Results indicated that rabbits fed the diet with low digestible energy (LDE) had reduced body gain/feed intake on days 1 to 14 and 1 to 36 (P < 0.05), increased the apparent total tract digestibility (ATTD) of neutral detergent fiber, acid detergent fiber (ADF), and n-free extract, and decreased the ATTD of gross energy (GE), crude fiber, and organic matter (OM; P < 0.05). The LDE diet upregulated the gene abundance levels of duodenum junctional adhesion molecule-3 (JAM-3) and downregulated the ileum toll-like receptor 4, myeloid differentiation factor 88, and interleukin-6 (IL-6; P < 0.05). Activities of amylase, lipase, trypsin, and the immunoglobulin M content in the jejunum were decreased in the LDE treatment group (P < 0.05). Dietary betaine supplementation increased the ATTD of GE, dry matter (DM), ADF, and n-free extract by LDE (P < 0.05). The villus height, crypt depth, and goblet cell numbers were decreased, and the villus-crypt ratio was increased in the duodenum (P < 0.05). The gene abundance levels of duodenum IL-2 were downregulated, and the duodenum JAM-2 and JAM-3 were upregulated (P < 0.05). Furthermore, the addition of betaine to the LDE diet increased the ATTD of GE, DM, and OM in rabbits (P < 0.05). Gene abundance levels of ileum IL-6 and duodenum JAM-3 were upregulated (P < 0.05). In summary, LDE diets can reduce the activity of intestinal digestive enzymes and decrease the ATTD of nutrients. However, the addition of betaine to LDE diets improved the intestinal barrier structure and nutrient ATTD in rabbits, with better results when betaine was added at an additive level of 500mg/kg.

Apparent total tract nutrient digestibility of frozen raw, freeze-dried raw, fresh, and extruded dog foods and their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs.

Various pet food diet formats are available, but many are poorly studied. The objective of this study was to determine the apparent total tract macronutrient digestibility (ATTD) of frozen raw, freeze-dried raw, fresh, and extruded dog foods and assess their effects on serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Ten beagle dogs (4.10 ± 0.74 yr) were used in a replicated 5 × 5 Latin square study to test the following diets: Chicken and Barley Recipe (extruded; Hill's Science Diet [EXT]), Chicken and White Rice Recipe (fresh; Just Food for Dogs [FRSH]), Chicken Formula (frozen raw; Primal [FRZN]), Chicken and Sorghum Hybrid Freeze-dried Formula (freeze-dried raw; Primal [HFD]), and Chicken Dinner Patties (freeze-dried raw; Stella & Chewy's [FD]). The experiment was composed of five 35-d periods, with each ending with fecal and blood collections. Data were analyzed using Mixed Models in SAS 9.4, with P < 0.05 being significant. Treatment was a fixed effect and dog a random effect. Protein ATTD was higher for FRZN and FD than other diets and higher for HFD than FRSH and EXT. Fat ATTD was higher for HFD than FRZN and EXT and lower for EXT than other diets. Fecal output was higher for dogs fed EXT than those fed other diets and higher for dogs fed FRSH than those fed FRZN, HFD, or FD. Fecal pH was lower in dogs fed EXT and FRSH than those fed other diets. Fecal scores were higher (looser) in dogs fed EXT and FRSH than those fed FRZN and FD. Fecal dry matter was higher in dogs fed FD than those fed other diets and higher in those fed FRZN and HFD than those fed EXT and FRSH. In general, fecal short-chain fatty acids were highest in dogs fed EXT, intermediate in dogs fed FRSH and HFD, and lowest in dogs fed FRZN and FD. Fecal isobutyrate and isovalerate were highest in dogs fed HFD, lowest in dogs fed FRSH, and intermediate in dogs fed other diets. Fecal primary bile acids were higher, while secondary bile acids were lower in dogs fed FRSH than in dogs fed other diets. Fecal microbiota were greatly impacted by diet, with alpha diversity, beta diversity, and relative abundances of over 40 bacterial genera being different among treatments. This study shows that dietary format may lead to great differences in nutrient digestibility and fecal characteristics, metabolites, and microbiota. More research is needed to distinguish the effects of ingredient source, processing method, and nutrient composition.

Lactational performance, enteric methane emission, and nutrient utilization of dairy cows supplemented with botanicals

The objective of this study was to evaluate lactational performance, enteric gas emissions, ruminal fermentation, nutrient use efficiency, milk fatty acid profile, and energy and inflammatory markers in blood of peak-lactation dairy cows fed diets supplemented with Capsicum oleoresin or a combination of Capsicum oleoresin and clove oil. A 10-wk randomized complete block design experiment was conducted with 18 primiparous and 30 multiparous Holstein cows. Cows were blocked based on parity, days in milk, and milk yield (MY), and randomly assigned to 1 of 3 treatments (16 cows/treatment): (1) basal diet (CON); (2) basal diet supplemented with 300 mg/cow per day of Capsicum oleoresin (CAP); and (3) basal diet supplemented with 300 mg/cow per day of a combination of Capsicum oleoresin and clove oil (CAPCO). Premixes containing ground corn (CON), CAP, or CAPCO were mixed daily with the basal diet at 0.8% of dry matter intake (DMI). Supplementation of the diet with CAP or CAPCO did not affect DMI, MY, milk components, and feed efficiency of the cows. Body weight (BW) was increased during the last 2 wk of the experiment by CAP and CAPCO, compared with CON. The botanicals improved BW gain (0.85 and 0.66 kg/d for CAP and CAPCO, respectively, compared with -0.01 kg/d for CON) and CAP enhanced the efficiency of energy utilization, compared with CON (94.5% vs. 78.4%, respectively). Daily CH4 emission was not affected by treatments, but CH4 emission yield (per kg of DMI) and intensity (per kg of MY) were decreased by up to 11% by CAPCO supplementation, compared with CON and CAP. A treatment × parity interaction indicated that the CH4 mitigation effect was pronounced in primiparous but not in multiparous cows. Ruminal molar proportion of propionate was decreased by botanicals, compared with CON. Concentrations of trans-10 C18:1 and total trans fatty acids in milk fat were decreased by CAP and tended to be decreased by CAPCO, compared with CON. Total-tract apparent digestibility of nutrients was not affected by treatments, except for a tendency for decreased starch digestibility in cows supplemented with botanicals. Blood concentrations of β-hydroxybutyrate, total fatty acids, and insulin were not affected by botanicals. Blood haptoglobin concentration was increased by CAP in multiparous but not in primiparous cows. Lactational performance of peak-lactation dairy cows was not affected by the botanicals in this study, but they appeared to improve efficiency of energy utilization and partitioned energy toward BW gain. In addition, CH4 yield and intensity were decreased in primiparous cows fed CAPCO, suggesting a potential positive environmental effect of the combination of Capsicum oleoresin and clove oil supplementation.

Extruded diet macronutrient digestibility: plant-based (vegan) vs. animal-based diets in client-owned healthy adult dogs and the impact of guardian compliance during in-home trials

IntroductionPlant-based (vegan) diets for dogs are commercially available, however, research investigating long-term nutritional adequacy of these diets is scarce. Use of client-owned animals has become increasingly popular for apparent total-tract nutrient digestibility (ATTD) studies, yet low guardian compliance with the study protocol, such as providing daily dietary intake information, is a challenge. However, the impact of low diet reporting compliance on the overall ATTD results is unknown.MethodsSixty-one, client-owned healthy adult dogs completed a randomized, double-blinded longitudinal study. Dogs were randomly assigned into two groups that were fed either a commercial extruded meat-based diet (MEAT, n=30) or an experimental extruded vegan diet (PLANT, n=31) for 12 weeks. At the end of the study, pet guardians performed a 72-hour total fecal collection for ATTD assessment. Pet guardians were asked to complete a food diary for the duration of the trial, however only a subset of guardians (n=35) provided this food diary at the end of the study.ResultsNo evidence of an association between pet guardians providing a food diary and apparent digestibility coefficients (ADC) of crude protein (CP) (p=0.14), crude fat (EE) (p=0.72), and dry matter (DM) (p=0.68) was found. Apparent digestibility coefficients for CP (p=0.52), EE (p=0.78), and DM (p=0.43) did not differ between PLANT and MEAT. Body weight and age were found to be associated with CP (p=0.03) and DM (p=0.01) digestibility, but no association with EE (p=0.07) digestibility was present.DiscussionThese results indicate that vegan- and animal-based diets with similar nutrient profiles can have comparable nutrient digestibility. Moreover, presence or absence of a guardian-reported food diary had no effect on the overall results of the ATTD study. Further studies investigating guardian compliance for ATTD trials are needed to develop a standardized protocol and reduce current challenges and limitations related to pet guardian’s participation in digestibility trials.