Apparent Digestibility Of Organic Matter Research Articles

Effects of Dietary Mulberry Leaf Powder in Concentrate on the Rumen Fermentation and Ruminal Epithelium in Fattening Hu Sheep.

Simple SummaryRumen is the center of nutrient digestion, absorption and metabolism of ruminants. Ruminal microbes such as cellulolytic bacteria degrade the feed nutrients into smaller molecules, which are absorbed into the body mainly through rumen epithelium. Our study found that mulberry leaf powder supplementation improved the development of rumen epithelium, especially stratum basale, the most important layer of rumen epithelium for the energy metabolism. Our study suggests that supplementing ruminants with mulberry leaf powder may be one of the nutritional strategies that can improve the digestion and absorption performance of ruminants.Mulberry leaves have been used as a protein source in replacing concentrates of domestic animals, however, little is known about the relationship between supplementation level and the development of rumen epithelium. This experiment aimed to investigate the effects of different proportions of mulberry leaf powder (MLP) in dietary concentrate on rumen fermentation and rumen epithelium morphology in fattening Hu sheep. Forty three-month-old male Hu sheep with an initial body weight of 16.5 ± 0.6 kg (BW ± SD) were chosen and randomly divided into five treatments: 0% (control), 15% (T15), 30% (T30), 45% (T45) and 60% (T60) of MLP in concentrate, respectively. The results showed that the dry matter intake (DMI) and average daily gain (ADG) in treatments T15 and T30 have no significant difference with respect to the control treatment, but DMI and ADG in treatments T45 and T60 were lower than the control treatment (p < 0.05). The apparent digestibility of organic matter (OM) and neutral detergent fiber (NDF) increased linearly and quadraticly as MLP supplementation increased (p < 0.05). The concentration of ammonia (NH3-N) trended to decrease linearly with the increase of MLP supplementation (p < 0.1), whereas the microbial protein (MCP) concentration increased linearly as MLP supplementation increased (p < 0.05). In the results of rumen epithelium morphology, the width of stratum corneum was reduced, whereas the width of ruminal papillae increased (p < 0.05), and the width of stratum granulosum and stratum basale also increased as MLP increased. In summary, MLP supplementation could improve nutrient digestibility, the development of rumen papillae and stratum basale. However, high content MLP (45%–60%) supplementation decreased the growth and food intake performance of fattening Hu sheep. Therefore, 30% MLP is recommended to supplement in concentrate for fattening Hu sheep.

Effect of maturity stage at harvest and kernel processing of whole crop wheat silage on digestibility by dairy cows

The study aimed to explore whether digestibility by cows of whole crop wheat silage harvested at two different dough stages of maturity was impaired due to its content of whole kernels. Wheat was harvested at early (ED) and soft-to-hard (SHD) dough and preserved as roundbale silage. After five months of storage, half of silage from each maturity stage was processed using a roller mill. Early dough silages contained 334 g dry matter (DM)/kg and 110 g starch/kg DM whereas SHD silages contained 423 g DM/kg and 254 g starch/kg DM.Total tract apparent digestibility and milk production by dairy cows was studied in a 2 × 2 factorial arrangement of silages harvested at the two maturity stages, either unprocessed or processed before feeding. Eight dairy cows were assigned to two Latin squares with four 3-week periods. Diets consisted of wheat silages offered ad libitum as the sole forage supplemented with 7.5 kg concentrates.Cows consumed on average 14.1 kg DM of wheat silage, 0.6 kg DM more of SHD than of ED silage (P < 0.001), and 0.4 kg DM more of processed than of unprocessed silage (P < 0.001). Apparent organic matter digestibility of wheat silage, calculated by difference, was 0.62 and 0.60 (P = 0.02) for ED and SHD respectively, and the respective starch digestibility was 0.98 and 0.99 (P = 0.02). There was no main effect (P > 0.20) of processing on total tract digestibility for any nutrient, but a weak interaction (P = 0.08) suggesting that starch digestibility was slightly higher in unprocessed than in processed wheat silage from SHD with an opposite tendency for ED. Daily yields of protein and lactose were higher, and milk yield tended to be higher (P = 0.07), with processed than with unprocessed silage from ED, as expected due to higher forage intake, whereas no effect of processing was found in SHD silage, in spite of higher intake. Soft-to-hard dough diets contained a high load of starch plus sugar compared with fibre. This might have influenced the rate and extent of ruminal neutral detergent fibre digestion. It is concluded that starch in wheat kernels harvested at the soft-to-hard dough stage or earlier, at a DM concentration in wheat silage up to 430 g/kg, is completely digested in dairy cows without processing.

Potential roles of nitrate and live yeast culture in suppressing methane emission and influencing ruminal fermentation, digestibility, and milk production in lactating Jersey cows

Concern over the carbon footprint of the dairy industry has led to various dietary approaches to mitigate enteric CH4 production. One approach is feeding the electron acceptor NO3-, thus outcompeting methanogens for aqueous H2. We hypothesized that a live yeast culture (LYC; Saccharomyces cerevisiae from Yea-Sacc 1026, Alltech Inc., Nicholasville, KY) would stimulate the complete reduction of NO3- to NH3 by selenomonads, thus decreasing the quantity of CH4 emissions per unit of energy-corrected milk production while decreasing blood methemoglobin concentration resulting from the absorbed intermediate, NO2-. Twelve lactating Jersey cows (8 multiparous and noncannulated; 4 primiparous and ruminally cannulated) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Cattle were fed diets containing 1.5% NO3- (from calcium ammonium nitrate) or an isonitrogenous control diet (containing additional urea) and given a top-dress of ground corn without or with LYC, with the fourth week used for data collection. Noncannulated cows were spot measured for CH4 emission by mouth using GreenFeed (C-Lock Inc., Rapid City, SD). The main effect of NO3- decreased CH4 by 17% but decreased dry matter intake by 10% (from 19.8 to 17.8 kg/d) such that CH4:dry matter intake numerically decreased by 8% and CH4:milk net energy for lactation production was unaffected by treatment. Milk and milk fat production were not affected, but NO3- decreased milk protein from 758 to 689 g/d. Ruminal pH decreased more sharply after feeding for cows fed diets without NO3-. Acetate:propionate was greater for cows fed NO3-, particularly when combined with LYC (interaction effect). Blood methemoglobin was higher for cattle fed NO3- than for those fed the control diet but was low for both treatments (1.5 vs. 0.5%, respectively; only one measurement exceeded 5%), indicating minimal risk for NO2- accumulation at our feeding level of NO3-. Although neither apparent organic matter nor neutral detergent fiber digestibilities were affected, apparent N digestibility had an interaction for NO3- × LYC such that apparent N digestibility was numerically lowest for diets containing both NO3- and LYC compared with the other 3 diets. Under the conditions of this study, NO3- mitigated ruminal methanogenesis but also depressed dry matter intake and milk protein yield. Based on the fact that few interactions were detected, LYC had a minimal role in attenuating negative cow responses to NO3- supplementation.

Effects of replacing soybean meal, soy protein concentrate, fermented soybean meal or fish meal with enzyme-treated soybean meal on growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology in weaned pigs

The present study was conducted to evaluate the effects of replacing soybean meal, soy protein concentrate, fermented soybean meal or fish meal with enzyme-treated soybean meal on growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology in weaned pigs. A total of 216 weaned pigs (initial BW:6.69 ± 0.99 kg) were blocked by BW and sex, and randomly assigned to 6 dietary treatments. Each treatment had 6 replicate pens with 6 pigs (3 barrows and 3 gilts) per pen. The experimental period was divided into 2 stages: phase 1 (d 0 to 14) and phase 2 (d 14 to 28). During d 0 to 14, pigs in ESBM-1 or ESBM-2 had greater (P < 0.05) average daily gain (ADG) than those in CON, SPC or FSBM. On d 14, the apparent total tract digestibility (ATTD) of dry matter (DM), organic matter (OM), crude protein (CP) and gross energy (GE) in pigs fed FM, ESBM-1 and ESBM-2 were greater (P < 0.05) than pigs fed the CON. Pigs fed FM, ESBM-1 and ESBM-2 had higher (P < 0.05) concentrations of superoxide dismutase (SOD), and had lower (P < 0.05) concentration of malondialdehyde (MDA) compared with CON. The concentrations of immunoglobulins G (IgG) and immunoglobulins M (IgM) were higher (P < 0.05) in pigs fed the ESBM-1 and ESBM-2 than pigs fed the CON, SPC and FSBM. On d 28, pigs in ESBM-2 had greater (P < 0.05) ATTD of CP and GE than those in CON, SPC and FSBM. Compared with the CON, SPC and FSBM, pigs in ESBM-2 had higher (P < 0.05) activity of SOD, glutathione peroxidase (GSH-Px) and T-AOC. But the MDA concentration was lower (P < 0.05) in FM, ESBM-1 and ESBM-2 than in CON. The villus height of duodenum was greater (P < 0.05) in ESBM-2 than in other treatments, and the villus height to crypt depth ratio of duodenum was greater (P < 0.05) in ESBM-2 than in CON, SPC and FSBM. In conclusion, enzyme-treated soybean meal can replace soybean meal, soy protein concentrate soy protein concentrate, fermented soybean meal or fish meal in weaned pig diets by improving the growth performance, nutrient digestibility, antioxidant capacity, immunity and intestinal morphology of weaned pigs.

Effects of feeding UFA-rich cold-pressed oilseed cakes and sainfoin on dairy ewes’ milk fatty acid profile and curd sensory properties

A lactation study was carried out utilizing 72 ewes in a 2 × 3 factorial arrangement involving two forages: Tall fescue (FES) and sainfoin (SAIN) hays; and 3 concentrates, which contained hydrogenated prilled palm fat (CTR), cold-pressed sunflower cake (SUN) or cold-pressed rapeseed cake (RPS) as fat sources. Ewes were divided into 6 equilibrated groups of 12 ewes each, according to milk yield and days in milk. Concentrates were offered individually and forage was group fed ad libitum. Milk yield was daily recorded; individual samples of milk were taken for fat, protein, lactose and for fatty acid (FA) composition analysis. Dry matter intake (DMI) and organic matter apparent digestibility (OMD) were estimated using two markers. Feeding behaviour was recorded for 48 h. Blood samples were collected for non-esterified fatty acids, blood urea nitrogen and IGF-1 determinations. Curd acceptance test was carried out using a non-trained sensory panel using a 10-point line scale for the attributes of appearance, flavour, odour, texture and overall acceptability. Milk yield and composition were analysed using the MIXED procedure for repeated measures with fixed effects of concentrate, forage and week, their interaction and the initial record measured at week 0 as covariate, and day and ewe as random effects. Total, hay and concentrate DMI, OMD, plasma metabolites and milk FA profile were analysed using the GLM procedure. Feeding behaviour and sensorial data were analysed using the previous statistical model but without including a covariate. SUN reduced milk total saturated fatty acids (SFA) compared to CTR with both forages, while RPS only reduced SFA with SAIN. Polyunsaturated FA were increased with both cakes and SAIN. SUN increased n-6:n-3 ratio compared to CTR (+54%) and RPS (+62%), and SAIN reduced this ratio compared to FES (−27%). SUN reduced milk index of atherogenicity compared to CTR (up to −33%) with both forages, while RPS reduced (up to −31%) this index only with SAIN. Concentrate did not affect milk production, digestibility and intake, but SAIN increased these traits together with plasma IGF-1. Neither concentrate nor forage affected curd acceptance traits. Healthier milk can be obtained with cakes. Nevertheless the forage used in the ration seems to be of great importance. Neither cakes nor SAIN had a detrimental effect on digestibility, production performance or curd acceptance in lactating ewes.

Impacts of incremental substitution of soybean meal for canola meal in lactating dairy cow diets containing a constant base level of corn derived dried distillers’ grains with solubles

Optimal protein nutrition of dairy cattle is important to support efficient production of high producing lactating dairy cows. Canola meal (CM) and corn dried distillers’ grains with solubles (DDGS) have been primary protein meals on many dairy farms in the Western USA for over 10 years, but decreases in the relative price of soybean meal (SBM) has created interest in how best to include it in lactation diets containing CM and DDGS. Three pens of ˜310 high producing multiparous Holstein cows were fed diets supplying 0, 35 or 70 g/kg SBM on a dry matter (DM) basis, which largely replaced CM, in a way that held the proximate nutrient content of the diets constant. Diets were rotated through the pens in a Latin square design such that each pen of cows experienced each diet once. Milk and component yields were lowest at the highest SBM level (Quad P < 0.01) and body condition score change shifted from a net gain with the 0 g/kg SBM diet to a net loss with both SBM inclusive diets (Quad P = 0.07). Apparent digestibility of neutral detergent fiber, organic matter and crude protein (CP) were highest with the 35 g/kg SBM diet (Quad P < 0.04), but rumen microbial CP output was not treatment impacted. Plasma amino acids were judged to be within normal ranges for all treatments, but there was a 20% decline (Quad P = 0.04) in Met concentrations between the 35 and 70 g/kg SBM diets. When SBM was added to diets with a base level of DDGS (˜75 g/kg diet DM), largely in substitution for CM, there was a reduction in performance, particularly with the 70 g/kg SBM diet. While no unified hypothesis fully explains all results, the most likely reason for this decline in performance with the highest dietary addition level of SBM was judged to be a reduction in Met as a proportion of metabolized AA, which may have created a Met limitation to animal production.

Effect of wheat bran feruloyl oligosaccharides on the performance, blood metabolites, antioxidant status and rumen fermentation of lambs

The objective of this experiment was to investigate the effects of wheat bran feruloyl oligosaccharides (FOs) as an antioxidant supplement on performance, blood metabolites, antioxidant status and ruminal fermentation of lambs. Fifty, two-month-old crossbred male lambs (Dorper × Small-tail Han Sheep) with an initial body weight (BW) of 20.21 ± 3.36 kg were randomly assigned into five groups of ten animals each and fed basal diet with dietary wheat bran FOs supplementation at 0, 50, 100, 200 and 400 mg/kg feed, respectively. The experimental period lasted 56 days and was preceded by an adaption period of 14 days. The absorption spectrum of FOs product used in this study revealed the presence of an esterified feruloyl group. The esterified FA concentration of this product reached 0.99 mmol/g. The feed conversion ratio improved quadratically (P < 0.05) with increasing FOs supplementation at stage from 29–56 days and over the whole experiment. During 29–56 days, the average daily gain of the lambs receiving 100 and 200 mg/kg FOs tended to be higher than lambs receiving 400 mg/kg FOs (P = 0.06). The apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and neutral detergent fiber (NDF) were significantly reduced when lambs were fed the 400 mg/kg FOs diet (P < 0.05). Supplementing lambs with 50, 100 and 200 mg/kg FOs significantly increased serum concentrations of total protein (P < 0.05), meanwhile, the serum albumin concentration of treatment groups showed a tendency to be higher than the control group (P = 0.05). Serum total antioxidative capacity (T-AOC) tended to increase (P = 0.07) quadratically with increasing FOs supplementation, and glutathione peroxidase (GSH-Px) activity increased (P < 0.05) quadratically with increasing doses of FOs. Compared to the control group, the serum catalase (CAT) and superoxide dismutase (SOD) activity of lambs fed with the 50 and 100 mg/kg FOs diet was significantly (P < 0.05) higher. FOs-supplementation groups had higher serum glutathione (GSH) concentrations than the control (P < 0.05). In addition, the ruminal ammonia nitrogen concentration of lambs fed with the 200 mg/kg FOs diet tended to be lower (P = 0.07) than lambs fed with the 400 mg/kg FOs diet, but the concentrations of total volatile fatty acid (VFA), individual VFA and pH were not affected. These results demonstrated that FOs supplementation can promote growth performance, decrease ruminal ammonia nitrogen concentration and improve antioxidant properties by increasing antioxidant enzyme activities and GSH concentration in lambs. Therefore, wheat bran FOs could be used as a novel antioxidant for lamb diets.

Effect of cowpea (Vigna Unguiculata (L.) Walp) Stover dietary inclusion level on total tract apparent digestibility of nutrients in growing rabbits

Although agro-industrial co-products have low economic value as foods for human consumption, they may have potential value as animal feedstuffs. This experiment was carried out to evaluate the effect of cowpea stover inclusion in rabbits’ diet on growth performance and nutrient digestibility. A total of 180 animals were randomly assigned to 3 treatments (CS0, CS2 or CS4, with no inclusion, 20 or 40 g/kg of cowpea stover, respectively). Animal performance was evaluated between the 53&lt;sup&gt;rd&lt;/sup&gt; and 67&lt;sup&gt;th&lt;/sup&gt; d of age in 48 animals per treatment. The coefficients of total tract apparent digestibility (CTTAD) of organic matter, crude protein, neutral detergent fibre and gross energy were measured between 63 to 67 d of age in 12 animals per treatment. Results showed that, in general, CTTAD values were not affected by the inclusion of cowpea stover. Nevertheless, a trend towards a decrease in crude protein digestibility (&lt;em&gt;P&lt;/em&gt;=0.0848) was observed when including cowpea stover. This had a negative influence on digestible protein (P=0.0240) and on the ratio between digestible protein and digestible energy (&lt;em&gt;P&lt;/em&gt;=0.0231) for diet CS4. Rabbits showed normal figures for growth rate (on av. 46.8 g/d), feed intake (on av. 168.3 g/d) and feed conversion ratio (on av. 3.61). Future studies should assess the possibility of incorporating higher levels of cowpea stover while analysing the economic impact of this inclusion.

Effects of nitrogen source on the performance and feeding behavior of lambs fed a high concentrate diet containing pomegranate peel

This experiment was conducted to investigate the effects of protein degradability on the performance, nutrient digestibility, rumen fermentation and behavior of lambs fed diets containing pomegranate peel (PP). Twenty-four male Iranian Arabic lambs (mean ± standard deviation; 16.3 ± 1.3 kg BW) were assigned randomly into four groups of six lambs each in a completely randomized design for 94 days. Treatments were: 1) control diet (CON); 2) diet containing PP with lower Rumen Degradable Nitrogen (RDN) (Soybean meal, PSOY); 3) diet containing PP with higher RDN (Urea, PUREA) and 4) free choice between diet 2 and 3 (PFREE). Forage to concentrate ratio of the diets was 20:80. The final body weight and dry matter intake were unaffected by treatments (P < 0.05), but there was a tendency to lower final body weight in PP groups compared to the CON (P = 0.09). A total replacement of soybean meal with urea negatively affected feed conversion ratio and OM digestibility. Daily weight gain was highest in lambs when offered CON (0.221 kg) and lowest in PUREA (0.182 kg), with lambs receiving PSOY (0.210 kg) and free choice (0.196 kg) having intermediate values. Apparent total tract digestibility of dry matter, organic matter, crude protein and ADF showed a decrease in PP containing diets (P < 0.05). Animals fed by urea containing diet showed higher mean rumen pH, rumen NH3-N concentration and blood urea nitrogen than CON and PSOY. Differences in volatile fatty acids concentrations were limited to valerate, which was lower for PP diets (P < 0.01). Providing lambs with PP diets increased time spent eating (190.7 vs. 166.5 min. d; P < 0.05) and intake per visit (70.5 vs. 50.1 g DM; P < 0.01), however, eating rate (7.56 g of DM/min) remained unchanged among treatments. Similarly, there was an increase (P < 0.01) in rumination and chewing activities with PP diets. In the free-choice treatment, lambs showed an increase in rumination and chewing time compared to the CON and PSOY groups. PP-fed lambs showed lower time spent self-grooming, social behavior, and lying, compared with the CON. The results suggest that in PP containing diets, the replacement of soybean meal with urea can be achieved with some adverse effects on performance, with the feed conversion being improved when free choice was given between protein sources. The inclusion level of 21.0% PP was probably too high for fattening lambs fed by high concentrate diets to ensure optimal growth performance and nutrient digestibility.

Effects of Tea Saponin Supplementation on Nutrient Digestibility, Methanogenesis, and Ruminal Microbial Flora in Dorper Crossbred Ewe.

Simple SummaryGreenhouse gas emissions are a serious cause of global warming and climate change, and have become a common focus for all countries. Methane has been proven the second most commonly occurring greenhouse gas. Ruminants have been blamed for substantially contributing to methane emissions. Supplementation with tea saponin (TS) effectively decreased methane emissions and nitrogen emissions. It is not only beneficial for environmental protection, but also has potential economic benefits.Two experiments were conducted using Dorper × thin-tailed Han crossbred ewes. In experiment 1, eighteen ewes were randomly assigned to two dietary treatments (a basal diet, or the same basal diet supplemented with 2.0 g tea saponin (TS)/head/day) to investigate the effects of TS supplementation on nutrient digestibility and methane emissions. In experiment 2, six ewes with ruminal cannulae were assigned to the same two dietary treatments as in experiment 1 to investigate the effects of TS supplementation on rumen fermentation and microbial flora. TS supplementation increased the apparent digestibility of organic matter (OM) (p = 0.001), nitrogen (N) (p = 0.036), neutral detergent fibre (NDF) (p = 0.001), and acid detergent fibre (ADF) (p < 0.001). Urinary N (p = 0.001) and fecal N (p = 0.036) output were reduced, and N retention (p = 0.001) and nitrogen retention/nitrogen intake (p = 0.001) were increased. Supplementary TS did not decrease absolute methane emissions (p = 0.519) but decreased methane emissions scaled to metabolic bodyweight by 8.80% (p = 0.006). Ammonia levels decreased (p < 0.001) and total volatile fatty acid levels increased (p = 0.018) in response to TS supplementation. The molar proportion of propionate increased (p = 0.007), whereas the acetate:propionate ratio decreased (p = 0.035). Supplementation with TS increased the population of Fibrobacter succinogenes (p = 0.019), but the population of protozoans tended to decrease (p = 0.054). Supplementation with TS effectively enhanced the apparent digestibility of OM, N, NDF, and ADF, and decreased methane emissions scaled to metabolic bodyweight.

Hot topic: Selecting cattle for low residual feed intake did not affect daily methane production but increased methane yield

Reducing enteric methane (CH4) production and improving feed conversion efficiency of dairy cows is of high importance. Residual feed intake (RFI) is one measure of feed efficiency, with low RFI animals being more efficient in feed conversion. Enteric CH4 is an important source of digestible energy loss in ruminants and, because research in beef cattle has reported a positive relationship between RFI and daily CH4 production, we hypothesized that low RFI dairy heifers, which are more feed efficient, would produce less CH4/d. We measured the daily methane production (g of CH4/d), methane yield [g of CH4/kg of dry matter intake (DMI)], and CH4 per kilogram of body weight (BW) gain for 56 heifers (20-22 mo old) in a 2 × 2 factorial arrangement: factors included 2 breeds (Holstein-Friesian and Jersey; n = 28/breed), with equal numbers of animals previously determined as being either high [+2.0 kg of dry matter (DM)/d] or low RFI (-2.1 kg of DM/d; n = 28/RFI category). All heifers were commingled and offered unrestricted access to the same diet of dried alfalfa cubes. Between RFI categories, heifers did not differ in BW or BW gain but low RFI heifers had 9.3 and 10.6% lower DMI and DMI/kg of BW, respectively, than high RFI heifers. Similarly, RFI category did not affect CH4/d or CH4/kg of BWg, but CH4/kg of DMI was higher in low RFI heifers because of their lower DMI. These results might reflect more complete digestion of ingested feed in the more efficient, low RFI heifers, consistent with previous reports of greater apparent digestibility of organic matter. Holstein-Friesian heifers were heavier and consumed more total DM than Jersey heifers, but breed did not affect DMI/kg of BW or BWg. Jersey heifers produced less CH4/d, but not CH4/kg of DMI or CH4/kg of BWg. We detected no interaction between breed and RFI category in any of the variables measured. In conclusion, differences in RFI in dairy heifers did not affect daily CH4 production (g/d); however, low RFI heifers had a greater CH4 yield (g/kg of DMI) on a high forage diet.

Digestibility contributes to between-animal variation in feed efficiency in beef cows

Residual feed intake (RFI) is an alternative measure of feed efficiency (FE) and is calculated as the difference between actual and expected feed intake. The biological mechanisms underlying animal-to-animal variation in FE are not well understood. The aim of this study was to investigate the digestive ability of beef cows selected for RFI divergence as heifers, using two contrasted diets. Fifteen 4-year-old beef cows were selected from a total of 69 heifers based on their RFI following the feedlot test. The selected heifers were ranked into high-RFI (+ 1.02 ± 0.28, n = 8) and low-RFI (−0.73 ± 0.28, n = 7), and a digestibility trial was performed after their first lactation. Both RFI groups were offered two different diets: 100% hay or a fattening diet which consisted of a DM basis of 67% whole-plant maize silage and 33% high starch concentrates over four experimental periods (two per diet). A diet effect was observed on feed intake and apparent digestibility, whereas no diet × RFI interaction was detected (P > 0.05). Intake and apparent digestibility were higher in cows fed the fattening diet than in those fed the hay diet (P < 0.0001). DM intake (DMI) and organic matter apparent digestibility (OMd) were repeatable and positively correlated between the two subsequent periods of measurements. For the hay and fattening diets, the repeatability between periods was r = 0.71 and r = 0.73 for DMI and r = 0.87 and r = 0.48 for OMd, respectively. Moreover, both intake (r = 0.55) and OMd (r = 0.54) were positively correlated (P < 0.05) between the hay and fattening diets. Significant differences between beef cows selected for divergence in RFI as heifers were observed for digestive traits (P < 0.05), DM and organic matter (OM) apparent digestibility being higher for low-RFI cows. Overall, this study showed that apparent digestibility contributes to between-animal variation in FE in beef cows.

High-fibre high-lipid by-product pellets containing calcium oxide-treated oat hulls as a partial replacement for barley grain in finishing diets for beef cattle

Two studies were conducted to evaluate the effects of treating oat hulls with calcium oxide (CaO) prior to inclusion in a high-lipid by-product pellet (HLP) on dry matter intake (DMI), ruminal fermentation, and total-tract digestibility (Study 1) and growth performance (Study 2). In Study 1, six ruminally cannulated heifers were used in a replicated 3 × 3 Latin square design. Study 2 used 210 steers in 21 pens in a 113 d finishing study. Dietary treatments for both studies included a barley-based control diet (CON), a diet where HLP partially replaced barley grain (NT-HLP), and a diet where HLP contained oat hulls treated with 7.5% CaO [dry matter (DM) basis; CaO-HLP]. For Study 1, DMI and ruminal pH were not affected. Apparent total-tract digestibility of DM and organic matter (OM) were greater (P &lt; 0.05) for CON than NT-HLP and CaO-HLP. In Study 2, final body weight tended to be greater for NT-HLP and CaO-HLP than CON (P = 0.065). For CaO-HLP and NT-HLP, DMI was greater than CON (P &lt; 0.01), but average daily gain (ADG) (2.0 kg d−1) and gain:feed (G:F) (0.16 kg kg−1) were not different. Thus, HLP can partially replace barley grain in finishing diets without negatively affecting ruminal fermentation or growth performance, but treatment with CaO has no effect.

Apparent digestibility of dry matter, organic matter, protein and energy of native Peruvian feedstuffs in juvenile rainbow trout (Oncorhynchus mykiss)

Trout production is a growing activity in recent years but requires new alternative sources of feed to be sustainable over time. The objective of this research was to determine the apparent digestibility coefficient (ADC) of dry matter (DM), organic matter (OM), crude protein (CP) and digestible energy (DE) of kañiwa (Chenopodium pallidicaule Aellen), kiwicha (Amaranthus caudatus L), quinoa (Chenopodium quinoa Willd), beans (Phaseolus vulgaris L.), sacha inchi, (Plukenetia volubilis L) and jumbo squid (Dosidicus gigas) meal in juvenile rainbow trout. The experimental diets were composed of a 70% basal diet and 30% of any raw materials. The ADC was determined by the indirect method using insoluble ash as a non-digestible marker. Jumbo squid, sacha inchi and quinoa showed the highest values of ADC (%) of DM (84.5, 73.5 and 69.7), OM (89.1, 78.4 and 72.9), CP (93.2, 98.0 and 90.3), and DE (4.57, 4.15 and 2.95 Mcal/kg DM), respectively. The ADC values for kañiwa, kiwicha and bean were significantly lower. In conclusion, quinoa meal and jumbo squid meal have an acceptable digestibility but sacha inchi meal is a potential alternative for rainbow trout feeding in the future.

Net energy of oat bran, wheat bran, and palm kernel expellers fed to growing pigs using indirect calorimetry.

The objectives of this experiment were to (a) determine the effects of fiber increase in diets on heat production (HP), (b) determine the net energy (NE) of oat bran (OB), wheat bran (WB), and palm kernel expellers (PKE) fed to growing pigs using indirect calorimetry (IC). Twenty-four growing barrows (29.2±2.6kg) were randomly allotted to one of four diets with six replicate pigs per diet. Diets included a corn-soybean meal basal diet and three test diets containing 30% OB, WB or PKE, respectively. During each period, pigs were individually housed in metabolism crates for 20days, including 14days to adapt to the diets. On day (d) 15, pigs were transferred to the open-circuit respiration chambers for determination of daily total HP and were fed one of the four diets at 2.3MJ ME/kg body weight (BW)0.6 /day. Total feces and urine were collected for the determination of digestible energy (DE) and metabolizable energy (ME) and daily total HP was measured from d 15 to d 19 and fasted on day 20 for the measurement of fasting heat production (FHP). The apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and organic matter (OM) were greater (p<0.01) in pigs fed the basal diet compared with those fed the test diets. The ATTD of neutral detergent fiber (NDF) was lower (p<0.01) in pigs fed the WB diet compared with those fed the basal, OB, or PKE diets. The ATTD of ether extract (EE) in pigs fed the PKE diet was greater (p<0.01) compared with those fed the other diets. The average total HP and FHP in pigs fed the four diets were 1261 and 787 kJ/kg BW0.6 /d, respectively, and were not significantly affected by diet characteristics. The NE:ME ratio for diets ranged from 78.1 to 80.9%. The NE contents of OB, WB, and PKE were 10.93, 7.47, and 8.71 MJ/kg DM, respectively.

Social context modulates digestive efficiency in greylag geese (Anser anser)

In group-living animals, social context is known to modulate physiology, behaviour and reproductive output as well as foraging and nutritional strategies. Here we investigate the digestive efficiency of 38 individuals belonging to different social categories of a semi-feral and individually marked flock of greylag geese (Anser anser). During 9 consecutive days in winter 2017, when the ground was fully covered with snow (i.e. no grass or other natural forage available) and the accessible food was standardized, 184 individual droppings were collected and analysed to estimate the apparent digestibility of organic matter (ADOM). Lignin was used as an indigestible internal marker in the food and droppings. The digestive efficiency was higher in pairs with offspring as compared to pairs without offspring or unpaired birds. Furthermore, individuals with high ADOM were more likely to breed successfully in the following season than those with low ADOM. Our findings demonstrate that social status modulates digestive efficiency, probably via a chain of physiological mechanisms including a dampened stress response in individuals enjoying stable social relationships with and social support by their family members (i.e. their own pair-partner and offspring). Our findings underline the importance of the social network in modulating physiology, such as digestive efficiency, and ultimately reproductive success.

Mixed organic acids improve nutrients digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high-fiber diet

ObjectiveThe objective of this study was to investigate effects of mixed organic acids (MOA) on nutrient digestibility, volatile fatty acids composition and intestinal microbiota in growing-finishing pigs fed high wheat bran diet.MethodsSix crossbred barrows (Duroc×Landrace×Yorkshire), with an average body weight 78.8±4.21 kg, fitted with T-cannulas at the distal ileum, were allotted to a double 3×3 Latin square design with 3 periods and 3 diets. Each period consisted of a 5-d adjustment period followed by a 2-d total collection of feces and then a 2-d collection of ileal digesta. The dietary treatments included a corn-soybean-wheat bran basal diet (CTR), mixed organic acid 1 diet (MOA1; CTR+3,000 mg/kg OA1), mixed organic acid 2 diet (MOA2; CTR+2,000 mg/kg OA2).ResultsPigs fed MOA (MOA1 or MOA2) showed improved (p<0.05) apparent total tract digestibility (ATTD) of gross energy, dry matter and organic matter, and pigs fed MOA2 had increased (p<0.05) ATTD of neutral detergent fiber compared to CTR. Dietary MOA supplementation decreased (p<0.05) pH value, and improved (p<0.01) concentrations of lactic acid and total volatile fatty acids (TVFA) in ileum compared to CTR. Pigs fed MOA showed higher (p<0.05) concentration of acetic acid, and lower (p<0.05) content of formic acid in feces compared to CTR. Pigs fed MOA1 had increased (p<0.05) concentration of TVFA and butyric acid in feces. Pigs fed MOA1 showed higher concentration of Lactobacillus and lower concentration of Escherichia in feces compared to CTR.ConclusionDietary supplementation of MOA 1 or 2 could improve nutrients digestibility, TVFA concentration and intestinal flora in growing-finishing pigs fed high fiber diet.

In vitro screening of plants from the Brazilian Caatinga biome for methanogenic potential in ruminant nutrition.

Thirty-nine plants naturally found in Brazilian Caatinga semiarid biome were screened using an in vitro fermentability testing focused in apparent organic matter digestibility (aOMD), gas, methane (CH4), and short-chain fatty acid (SCFA) production. Three independent in vitro runs were carried out and plants were classified by CH4 concentration as proportion of gas and per unit of apparent digested organic matter (aDOM). According to its CH4 concentration on produced gas (mL/L), the plants were classified as low (> 110), medium (from 60 to 110), and high (< 60) anti-methanogenic potential. From evaluated plants, 3, 24, and 12 were classified as high, medium, and low anti-methanogenic potential. High anti-methanogenic potential plants Cnidoscolus phillacanthus (CnPh), Chloroleucon foliolosum (ChFo), and Anadenanthera macrocarpa (AnMa) produced 21.3, 34.3, and 35.9mL CH4/L of gas. Methane concentration for Myracrodruon urundeuva (MyUr) was 61.1mL/L and classified as medium potential. However, CH4 production per unit of aDOM was similar between MyUr and AnMa (3.35 and 2.68mL/g, respectively). Molar proportions of acetate and propionate in SCFA produced by ChFo fermentation were 0.02 and 0.78mmol/mol. Acetate to propionate ratios were 0.79, 0.03, 1.39, and 1.36 for CnPh, ChFo, AnMa, and MyUr, respectively. Greater aOMD were observed for Opuntia sp. and Calotropis procera (632 and 601g/kg, respectively), which were classified as medium mitigating potential plants. AnMa, ChFo, CnPh, and MyUr are promising anti-methanogenic plants for ruminants. Selecting forages to feed ruminants in Caatinga is a potential strategy for enteric CH4 emission reduction, and our in vitro results can support future research by indicating species to be evaluated in in vivo studies integrating mixed diets with performance, digestibility, and CH4 production, yield, and intensity. Graphical abstract ᅟ.

Hydroxyproline and starch consumption and urinary supersaturation with calcium oxalate in cats

The effect of extruded foods intake with different contents of starch, protein and hydroxyproline were evaluated on water balance, oxalate renal excretion, urine chemical composition and the relative urine supersaturation with calcium oxalate (RSSCaOx) in cats. Three complete and balanced diets were formulated with different proportions of starch, protein and hydroxyproline: STARCH, high starch and low protein and hydroxyproline content diet; SOY, high protein and low hydroxyproline and starch content diet; HYDROX, high hydroxyproline and protein, and low starch content diet. Twenty-four cats were used, with 8 replicate cats per diet. Animals were submitted to an adaptation period of 10 days, followed by 7 days for total feces and urine collection and 1 day for blood collection. Data were submitted to analysis of variance and means compared by Tukey’s test (P < 0.05). Non-normal data were analyzed using Kruskal-Wallis and Dunn tests (P < 0.05). According to each treatment, cats had significantly different intake of starch, crude protein and hydroxyproline (P < 0.05). For diets higher in protein and lower in starch, coefficient of total tract apparent digestibility (CTTAD) of organic matter (OM), crude protein (CP), and gross energy (GE) were higher (P < 0.05). The daily urinary volume and water intake via drinking bowl (P < 0.001) were higher for cats fed with high protein foods (SOY and HYDROX) (P < 0.05). Renal excretion of Cl, S, uric acid and urea increased for animals receiving SOY and HYDROX diets compared with cats on the STARCH diet (P < 0.05), following the increase in intake of protein and these minerals. Although high protein consumption is generally associated with low urinary pH, on the present study cats fed the SOY diet produced urine with higher pH values than those fed the STARCH diet, although the former is higher in protein (P = 0.004). Oxalate urine concentration and RSSCaOx were higher (P < 0.001) and oxalate renal excretion tended to be higher (P = 0.109) for cats fed STARCH and HYDROX diets than those fed with the SOY food, suggesting higher hepatocyte production of oxalate after higher starch and hydroxyproline consumption by cats. In conclusion, although the limitation of the use of practical diets with differences on chemical composition, elevated starch intake with low protein consumption reduced urine production, and the high starch and hydroxyproline increased oxalate urine concentration and RSSCaOx. However, none of these diets induced the production of supersaturated urine with calcium oxalate, because all cats produced urine in the undersaturated zone.

Effects of dietary protein levels and calcium salts of long-chain fatty acids on nitrogen mobilization, rumen microbiota and plasma fatty acid composition in Holstein bulls

The aim of this study was to investigate the impact of dietary crude protein (CP) levels and calcium salts of long-chain fatty acids (CSFA) on the nutrient intake and digestibility, nitrogen deposition, rumen fermentation characteristic and microbiota, plasma biochemical indexes and fatty acid composition in the Holstein bulls. Eight Holstein bulls was used in a 4 × 4 Latin Square design with 2 × 2 factorial diets, including two levels of CP (133 or 112 g/kg dry matter), and with or without 2.32 g/kg CSFA. The high CP level diets increased the CP intake and the CP apparent digestibility and the urinary nitrogen excretion (P = 0.001). Dietary supplementation with CSFA promoted the apparent digestibility of organic matter (P = 0.012). The diets of CSFA and high CP level raised the rumen ammonia nitrogen concentration (P = 0.009), and enhanced the isovalerate and valerate concentrations, respectively. The high CP diets improved the abundance of Butyrivibrio fibrisolvens (P = 0.037) and Megasphaera elsdenii (P = 0.023), while the CSFA reduced the abundance of methanogens (P = 0.047). High CP increased urea concentration (P = 0.008). Dietary supplementation with CSFA increased the cholesterol and the low-density lipoprotein cholesterol concentration in the plasma, and the proportion of C16:0, C18:1n9c and Δ9 desaturase C18, while it reduced the ratio of C21:1 and C22:0. The low CP diets reduced the protein waste and environmental pollution in the final stage of fattening Holstein bulls. Further study needs to be done to investigate the effect of CSFA on the CH4 emission in terms of microbial mechanism in the rumen.