Total Digestibility Research Articles

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.

Pulsed electric field (PEF) processing of microalga Chlorella vulgaris and its digestibility in broiler feed

Microalgae have potentially beneficial effects on animal health and nutritional value when added to feed. Crucial hereby is that intracellular bio-active molecules are released in the intestinal tract. Digestibility of Chlorella vulgaris and its impact on total digestibility of broiler feed is a first step in assessing its characteristics as feed supplement. Different methods could be used to increase the digestibility of the algae. Among other, pulsed electric field (PEF) and freezing to disrupt autotrophic (A) and heterotrophic (H) Chlorella vulgaris cells was assessed to increase their availability followed by in-vivo trials. In these trials effect of algae type (A and H) and effect of PEF-processing was evaluated on the apparent nutrient digestibility. Pulsed electric field showed to have a disruption efficiency of 83.90% and 79.20% for heterotrophic and autotrophic C. vulgaris respectively. Freezing C. vulgaris only showed efficiencies ranging from 3.86 to 11.58%. In the in-vivo trials, microscopic counting of intact C. vulgaris cells showed an increase in digested intact C. vulgaris cells of PEF-processed C. vulgaris compared to nonprocessed cells ranging from 12.16% to 15.20%. Autotrophic C. vulgaris had a higher digestibility compared to heterotrophic C. vulgaris, with an increase of 7.29, 9.44, and 17.29% in digestibility of C. vulgaris in the 1, 2, and 5% feed respectively. Feeds with PEF-processed C. vulgaris showed no significant increase in digestibility compared to nonprocessed C. vulgaris supplemented feeds. The 5% C. vulgaris feeds showed lower fat digestibility than the 1 and 2% and control feeds. Protein digestibility was lower for all C. vulgaris feeds compared to the control feed. There was a significant linear decreasing effect (P < 0.001) for all digestibility parameters. Except for crude ash digestibility, which first lowered for the 1 and 2% feeds, but then increased at 5% inclusion. Considering this study, including low dosages of 1 and 2% of C. vulgaris in broiler feed does not compromise its digestibility.

Effects of supplementing cassava root silage to grazing dairy cows on nutrient utilization, milk production and composition in the tropics.

The current study evaluated the effects of supplementing cassava root silage (CRS) to dairy cows grazing on Megathyrsus maximus cv Mombasa on nutrient intake and digestibility, as well as on milk production and composition. Ten primiparous Girolando cows with average body weight ± (SEM) of 373.45 ± (63.55) kg were used in a replicated 5 × 5 Latin square. Animals were subjected to five treatments: (I) grazing cows without supplementation (WCS); (II) grazing cows provided with 5kg DM of supplement without CRS (0g/kg DM of CRS) or including (III) 260, (IV) 520, and (V) 780g/kg DM of CRS. Statistical analyses were performed using the PROC MIXED of SAS with significance at P < 0.05. Intake of neutral detergent fiber (NDF) and ether extract decreased (P < 0.01), while intake of non-fiber carbohydrates increased (P < 0.01), with increased CRS in the diets. Total DM intake and digestibility of DM, and digestibility of nutritional components were lower (P < 0.03) in WCS animals compared to supplemented animals, except for intake and digestibility of NDF, which was the opposite. Milk yield (MY) and fat corrected milk (FCM), as well as all milk components were unaffected (P > 0.05) by CRS inclusion. In contrast, MY, FCM, protein, lactose, casein, and non-fat milk solids (NFMS) were greater for animals that received supplementation (P < 0.05), compared to animals WCS. Milk fat and total dry extract (TMS) did not differ (P > 0.11) between two groups. In conclusion, CRS may be a potential corn meal replacer in the supplement of dairy cows under tropical conditions.

Engineered algal systems for the treatment of anaerobic digestate: A meta-analysis

The objective of this review was to provide quantitative insights into algal growth and nutrient removal in anaerobic digestate. To synthesize the relevant literature, a meta-analysis was conducted using data from 58 articles to elucidate key factors that impact algal biomass productivity and nutrient removal from anaerobic digestate. On average, algal biomass productivity in anaerobic digestate was significantly lower than that in synthetic control media (p < 0.05) but large variation in productivity was observed. A mixed-effects multiple regression model across study revealed that biological or chemical pretreatment of digestate significantly increase productivity (p < 0.001). In contrast, the commonly used practice of digestate dilution was not a significant factor in the model. High initial total ammonia nitrogen suppressed algal growth (p = 0.036) whereas initial total phosphorus concentration, digestate sterilization, CO2 supplementation, and temperature were not statistically significant factors. Higher growth corresponded with significantly higher NH4–N and phosphorus removal with a linear relationship of 6.4 mg NH4–N and 0.73 mg P removed per 100 mg of algal biomass growth (p < 0.001). The literature suggests that suboptimal algal growth in anaerobic digestate could be due to factors such as turbidity, high free ammonia, and residual organic compounds. This analysis shows that non-dilution approaches, such as biological or chemical pretreatment, for alleviating algal inhibition are recommended for algal digestate treatment systems.

Supplementation of feedlot lambs with magnesium oxide and sodium bicarbonate: Effects on performance, nutrient digestibility, rumen environment, serum biochemistry and antioxidant indices

The present experiment was conducted to obtain an appropriate addition strategy of magnesium oxide (MgO) for feedlot lambs and to elucidate how the combined addition of MgO and sodium bicarbonate (NaHCO3) influences the growth performance and carcass characteristics of feedlot lambs. Sixty male Dorper-Hu hybrid lambs (32.76 ± 0.85 kg) were randomly assigned to 20 pens (3 lambs per pen; 5 pens per treatment). Lambs received a corn-based total-mixed ration (TMR, 80:20 concentrate to forage) without supplementation (CON) or with the inclusion (dry matter basis) of 15 g/kg NaHCO3 (SB), 2.5 g/kg MgO + 7.5 g/kg NaHCO3 (MG1) or 5 g/kg MgO + 7.5 g/kg NaHCO3 (MG2). Buffer addition effectively increased ruminal pH and water intake in feedlot lambs (P < 0.01). The MG2 group had lower dry matter intake (P ≤ 0.03), while the MG1 group showed higher average daily gain and lower feed-to-gain ratio than the other groups (P < 0.01). Compared to the CON and SB groups, MG1 and MG2 groups had greater total tract nutrient digestibility, except for the stage 1 of DM and ADF (P < 0.01). Adding MgO with NaHCO3 improved total volatile fatty acids concentration (P < 0.01). Microbial community analysis revealed enhanced Prevotella abundance in both MG1 and MG2 groups (P = 0.04). Additionally, MG1 and MG2 groups also both exhibited greater serum antioxidant capacity compared to CON and SB groups (P ≤ 0.03). The MG1 group showed greater dressing percentage, and ribeye area than other groups (P < 0.01). Overall, the recommended supplementation strategy for the lambs' diet was 2.5 g/kg MgO + 7.5 g/kg NaHCO3. The mixture of MgO and NaHCO3 enhanced the total tract nutrient digestibility, rumen fermentation, and serum antioxidant capacity in lambs, resulting in improved lamb growth and carcass performance.

Performance and nutrient digestibility of growing pigs fed highly or low fermentable coarse or finely ground fibre-rich feedstuffs

ABSTRACT Dietary fibre is mainly classified according to its chemical characteristics but structure and particle size of fibre-rich feedstuff can also be decisive for digestion and performance. So far, only few studies investigated this in pigs. This experiment aimed to compare coarse and finely ground dried hemp plants and apple pomace regarding performance and ileal and total tract nutrient digestibility of growing pigs. Coarse or finely ground apple pomace or dried hemp plants were added to the diet of 56 nine weeks old growing pigs (DanBred x Duroc), housed in flat decks with each 2 animals. The growing pigs received the experimental diets for three weeks while performance was recorded. Eight pigs per group were sacrificed and digesta and organ tissue sampled. The stomach health was evaluated by visually scoring of the mucosa integrity. Apparent ileal (AID) and total tract digestibility (ATTD) were calculated using titanium dioxide as marker. Statistical analyses were performed using two-way ANOVA (p < 0.05). The highest feed intake (fibre particle size, p = 0.018) and bodyweight gain (fibre particle size, p = 0.018; fibre source x particle size interaction, p = 0.040), was observed in animals fed finely ground apple pomace, while the feed conversion ratio was 8–12% lower in pigs fed finely ground fibre sources (p = 0.012). No differences in stomach mucosa integrity were detected between the groups. The relative pancreas (p = 0.045), stomach (p < 0.001), and jejunum (p = 0.010) weights were higher in animals fed diets containing apple pomace. In contrast, the relative liver, caecum and colon weights were not affected by fibre source or particle size. The AID of protein and amino acids was not affected, while ATTD was increased by fibre source (hemp vs. apple pomace) reducing faecal nitrogen excretion. The AID of calcium was increased when diets contained apple pomace (p < 0.001), while zinc AID and ATTD were enhanced when diets contained dried hemp (p = 0.016; p = 0.016, respectively). Our results suggest that the structure as well as the chemical characteristics should be considered in a future fibre evaluation system in pigs.

Macronutrient Analysis and In vivo Test in the Utilization of Barracuda Fish (Sphyraena barracuda) Asap Liquid as an Action to Meet Protein Needs

The smoking process has undergone significant development and liquid smoke has been widely used for the food industry as an ingredient that gives a distinctive aroma and flavor to food products. The purpose of this study was to determine the macronutrient quality of smoked fish and protein absorption in mice. Quality testing of barracuda smoked fish refers to SNI 2725: 2013. Test types include water content, ash content, protein content, fat content, pH, and Benzo[a]pyrene. In vivo analysis was conducted on mice to observe Protein Efficiencey Rate (PER), Net Protein Ratio (NPR), Total Protein Digestibility (TPD), Biological Value (BV), and Net Protein Utilization (NPU) values. Data were analysed with One-Way ANOVA. The results showed that the use of liquid smoke at a concentration of 5% had a significant effect (p &lt; 0.05) on the test of moisture content of 55.2 ± 0.50, ash content of 4.28 ± 0.02, protein content of 35.47 ± 0.23, fat content of 4.55 ± 0.08, pH 6.77 ± 0.05 and benzo[a]pyrene &lt; 0.02. The parameter results of TPD 78.21 ± 31.87, NPU 80.43 ± 3.75 in liquid smoked barracuda fish have higher values than traditional smoked barracuda fish, while PER 3.6 ± 4.06, NPR 4.06 ± 1.76 and BV 200 ± 4.24 have higher values in liquid smoked barracuda fish compared to traditional smoked barracuda fish. The addition of liquid smoke can to maintain product quality and improve the nutritional quality of protein because protein can be digested and absorbed by the body properly.

Optimizing dietary rumen-degradable starch to rumen-degradable protein ratio improves lactation performance and nitrogen utilization efficiency in mid-lactating Holstein dairy cows.

The dietary rumen-degradable starch (RDS) to rumen-degradable protein (RDP) ratio, denoted as the RDS-to-RDP ratio (SPR), has been proven to enhance in vitro rumen fermentation. However, the effects of dietary SPR in vivo remain largely unexplored. This study was conducted to investigate the effect of dietary SPR on lactation performance, nutrient digestibility, rumen fermentation patterns, blood indicators, and nitrogen (N) partitioning in mid-lactating Holstein cows. Seventy-two Holstein dairy cows were randomly assigned to three groups (24 head/group), balanced for (mean ± standard deviation) days in milk (116 ± 21.5), parity (2.1 ± 0.8), milk production (42 ± 2.1 kg/d), and body weight (705 ± 52.5 kg). The cows were fed diets with low (2.1, control), medium (2.3), or high (2.5) SPR, formulated to be isoenergetic, isonitrogenous, and iso-starch. The study consisted of a one-week adaptation phase followed by an eight-week experimental period. The results indicated that the high SPR group had a lower dry matter intake compared to the other groups (p < 0.05). A quadratic increase in milk yield and feed efficiency was observed with increasing dietary SPR (p < 0.05), peaking in the medium SPR group. The medium SPR group exhibited a lower milk somatic cell count and a higher blood total antioxidant capacity compared to other groups (p < 0.05). With increasing dietary SPR, there was a quadratic improvement (p < 0.05) in the total tract apparent digestibility of crude protein, ether extract, starch, neutral detergent fiber, and acid detergent fiber. Although no treatment effect was observed in rumen pH, the rumen total volatile fatty acids concentration and microbial crude protein synthesis increased quadratically (p < 0.05) as dietary SPR increased. The molar proportion of propionate linearly increased (p = 0.01), while branched-chain volatile fatty acids linearly decreased (p = 0.01) with increasing dietary SPR. The low SPR group (control) exhibited higher concentration of milk urea N, rumen ammonia N, and blood urea N than other groups (p < 0.05). Despite a linear decrease (p < 0.05) in the proportion of urinary N to N intake, increasing dietary SPR led to a quadratic increase (p = 0.01) in N utilization efficiency and a quadratic decrease (p < 0.05) in the proportion of fecal N to N intake. In conclusion, optimizing dietary SPR has the potential to enhance lactation performance and N utilization efficiency. Based on our findings, a medium dietary SPR (with SPR = 2.3) is recommended for mid-lactating Holstein dairy cows. Nevertheless, further research on rumen microbial composition and metabolites is warranted to elucidate the underlying mechanisms of the observed effects.

Effect of Direct Fed Microbial (DFM) on in-vitro Methanogenesis and Dry Matter Digestibility

The in-vitro rumen fermentation study was conducted to evaluate the effect of supplementation of direct-fed microbial (DFM) in the total mixed ration (TMR) on total gas production, methanogenesis and dry matter digestibility by using rumen liquor of adult Surti buffaloes. DFM was supplemented at 0, 1, 2, 3, 4, 5, 6, 7, and 8% with TMR (65% Straw and 35% concentrate) for in-vitro gas production trials. The result of the in-vitro study revealed significantly (P&lt;0.05) higher IVDMD (57.03%) and lower CH4 production (3.20 ml CH4/100 mg DDM) at a 3% level of DFM supplementation in TMR. Based on the overall results of in-vitro studies 3% level of DFM supplementation was found to be most suitable for further in-vivo studies in adult Surti buffaloes.

Elemental Analysis of Dietary Supplements by Microwave-Induced Plasma–Optical Emission Spectrometry (MIP-OES) With Ultrasound-Assisted Extraction (UAE)

The purpose of this study was to demonstrate the feasibility of determining metals (Cr, Mn, Zn, Fe, and Cu) in commercial dietary supplements using microwave-induced plasma optical emission spectrometry (MIP OES) after fast ultrasound-assisted extraction. Various parameters affecting the extraction process, such as the nature and concentration of the extractant solution, sonication time, and sample mass, were evaluated. Under the optimal conditions, it was possible to quantitatively extract metals from the samples by sonicating 1.0 g of the supplement dispersed throughout 25 mL of a 1.0 mol L−1 HNO3 for only 5 min. The developed method was applied to determine the analytes in four dietary supplements available in the Brazilian market. The results obtained with the extraction method were compared with the values obtained when the samples were completely mineralized with concentrated HNO3 in a microwave oven. There were no statistical differences between the developed and reference methods when the paired Student’s t-test was applied with a 95% confidence level. The application of ultrasound-assisted extraction was demonstrated to be advantageous compared to total sample digestion. This approach allowed the use of a higher mass of the sample, thereby enhancing the analytical capability of the method. Furthermore, employing less severe conditions, such as lower energy and a diluted acid solution, simplified and reduced the cost of the procedure compared to mineralization.

Effects of saturated fatty acids with lysophospholipids on production and nutrient digestibility in lactating cows

The objective of the experiment was to determine the effects of supplemental saturated fatty acid (SFA) sources, lysophospholipids (LPL), and their interaction on production and nutrient digestibility in lactating dairy cows. The experiment was conducted with 48 cows in a randomized complete block design. Cows were blocked (total 12 blocks) by parity and days in milk and randomly assigned to 4 dietary treatments in each block (2 × 2 factorial arrangement), i.e., 2 sources of fat supplements, C16:0 (palmitic acid, PA)- or C18:0 (stearic acid, SA)-enriched fat, with or without LPL. The experiment was conducted for 6 wk to measure daily dry matter intake and milk yield and weekly milk composition. During the last week of the experiment, spot fecal and urine samples were collected to determine total-tract nutrient digestibility. Milk samples in the last week were also collected to analyze for milk fatty acid (FA) profile. All data were analyzed using the mixed procedure of SAS where block was used as a random effect and FA, LPL, and the interaction of FA by LPL were used as fixed effects. Week and interactions of week by FA or LPL were included for production measures. Different sources of SFA did not affect dry matter intake and milk yield. However, PA increased (39.7 vs. 36.8 kg) energy-corrected milk compared with SA due to increased milk fat yield. No effect of LPL on production measures was observed. Total-tract digestibilities of dry matter, organic matter, crude protein, and total FA were not different between PA and SA, but PA increased (41.4 vs. 38.8%) neutral detergent fiber digestibility compared with SA. Supplementation of LPL increased (64.7 vs. 60.5%) total FA digestibility, especially 18-carbon FA (74.1 vs. 68.2%). An interaction of SFA by LPL was found for 16-carbon FA digestibility. The PA diet increased the concentration of 16-carbon FA in milk fat and SA increased the concentration of preformed FA (≥18 carbons). Supplementation of LPL decreased the concentration of trans-10 C18:1. No difference in N utilization and excretion among treatments was observed. In conclusion, PA was more effective in improving milk fat yield of lactating cows compared with SA. Supplementation of LPL increased digestibility of total FA, especially 18-carbon FA but did not affect production.

Comparison of forages’ digestion levels for different in vitro digestion techniques in horses

Forages are widely used in horse diets. Different in vitro techniques are being tried to determine the fermentation levels of forages in the horse digestive tract. This study aimed to evaluate the digestion levels of four dry forages commonly used in horse nutrition: alfalfa herbage, meadow hay, wheat straw, and Italian ryegrass. In vitro total digestion (TDT), in vitro Sunvold-large intestine digestion (SDT) and in vitro Menke-large intestine digestion (MDT) techniques were compared. The study determined in vitro true dry matter digestion (T-DMD), in vitro true organic matter digestion (T-OMD) and in vitro true neutral detergent fibre digestion (T-NDFD). Additionally, concentrations of straight short-chain fatty acids (SCFAs; acetic acid - AA, propionic acid , butyric acid, and valeric acid ) and branched short-chain fatty acids (BSCFA) were assessed. The highest in vitro T-DMD, T-OMD and T-NDFD values were determined by the in vitro TDT for the four forages (p<0.05). In vitro T-DMD and T-OMD values of alfalfa herbage were higher than those of Italian ryegrass, meadow hay and wheat straw in the in vitro TDT (p<0.001). In addition, in vitro T-DMD and T-OMD values of alfalfa herbage in the in vitro SDT were higher than those of meadow hay and wheat straw (p<0.001). In the in vitro TDT, the molarity of AA, total SCFA and BSCFA in the digestion fluid of alfalfa herbage was higher than those of other forages (p<0.05). The in vitro total enzymatic+fermentative digestion technique for horse forages revealed higher values than the in vitro fermentative digestion techniques. In general, the higher the non-structural carbohydrate and crude protein contents in the forage, the higher the results of the in vitro TDT compared to the other techniques.

Geochemistry of Rare Earth Elements in Pahang River Sediment, Malaysia

Rare earth elements (REE) are a set of 17 chemically similar metallic elements including 15 lanthanides, scandium and yttrium. The current status of REE as a global strategic commodity has encouraged the identification of REE ore deposits. This research is carried out to identify the mining feasibility of fluvial sediment REE and to understand the sediment's physical and chemical characteristics and effects on the geochemical behaviour of REE in the longest river of Peninsular Malaysia namely Pahang River. Surface sediment samples were collected along Pahang River (n=44) in approximately 10 km distance intervals. The sediment samples were analyzed using XRF to determine the major oxide content. Meanwhile, REE content in the sediment samples was extracted using the Total Digestion method and analysed using ICP-MS. The results show the average value of ΣREE at surface sediments of the Pahang River is 42.58 ppm and can be considered too low to be economically mined. Each area shows higher fractionation of light REE than heavy REE with negative europium anomalies, suggesting sediments in this area were derived from felsic rocks. The concentration of REE in Pahang River surface sediments was controlled by the porosity and organic matter as showed by the correlation of ΣREE with porosity (R2=0.65) and organic matter content (R2=0.71). In conclusion, this research's findings are generally useful for further REE mineral exploration and fluvial sediment environmental monitoring.

Characterization of ruminal degradation, intestinal digestion and total true nutrient supply to dairy cows from feedstocks and coproducts from Canola bio-oil processing: Impact by source origin.

The objective of this study was to characterize ruminal degradation, intestinal digestion and total true nutrient supply to dairy cows from canola feedstock (canola seeds) and coproducts (meal and pellets) from bio-oil processing which were impacted by source origin. The feedstocks and coproducts (mash, pellet) were randomly collected from five different bio-oil processing plants with five different batches of samples in each bio-processing plant in Canada (CA) and China (CH). In situ rumen degradation kinetics were determined using four fistulated Holstein cows with incubation times at 0, 2, 4, 8, 12, 24 and 48 h. Intestinal digestions were determined using the three-step in vitro method with preincubation at 12 h. The DVE/OEB and National Research Council systems were applied to evaluate the truly absorbable nutrient supply to dairy cows and feed milk values (FMVs). The results showed that in situ undegradable fractions (U) (p = 0.025) were higher in CA meals, and potentially degradable fraction of D was higher (p = 0.016) in CH meals. CH meals had higher total digestible dry matter (TDDM, p = 0.018) and intestinal digestibility of protein (dIDP, p = 0.016). Canola meals from CA had lower MREE (microbial protein synthesized in the rumen based on available rumen degradable protein; p = 0.011) and DVME (rumen synthesized microbial protein digested in the small intestine; p = 0.011) and had higher ECP (endogenous protein in the small intestine, p = 0.001) and absorbed endogenous crude protein (truly absorbed ECP in the small intestine) than CH (p = 0.001). The FMV evaluated based on the metabolic protein and net energy showed no differences between CA and CH in both coproducts and feedstocks.

Improved in vitro gastrointestinal digestion protocol mimicking brush border digestion for the determination of the Digestible Indispensable Amino Acid Score (DIAAS) of different food matrices

The Digestible Indispensable Amino Acid Score (DIAAS) is the new gold standard method for the assessment of protein nutritional quality. The DIAAS is evaluated with in vivo models, that are complex, constraining and costly. There is still no established method to assess it in vitro. In this study, we proposed to add a jejunal-ileal digestion phase to the standardized in vitro gastrointestinal digestion protocol developed by the International Network of Excellence on the Fate of Food in the Gastrointestinal Tract (INFOGEST protocol) to mimic brush border digestion and to enable DIAAS assessment in vitro in a more physiologically relevant manner. This jejunal-ileal digestion phase was performed with a porcine intestinal aminopeptidase as an alternative to brush border membrane extract, which is more difficult to obtain in a standardized way. This modified INFOGEST protocol was applied to various food matrices (faba bean, pea and soy flours, whey protein isolate and caseins) and the results were compared to published in vivo data to assess the model’s physiological relevance. The addition of the jejunal-ileal digestion phase lead to a significant (p < 0.05) increase of 31 and 29 % in free and total amino acid digestibility, respectively, and of 83 % on average for the in vitro DIAAS values for all food matrices. Although the in vitro DIAAS remained underestimated compared to the in vivo ones, a strong correlation between them was observed (r = 0.879, p = 0.009), stating the relevance of this last digestion phase. This improved digestion protocol is proposed as a suitable alternative to evaluate the DIAAS in vitro when in vivo assays are not applicable.

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.

Effects of feeding hybrid rye grain as a replacement for barley grain on dry matter intake, ruminal fermentation, and the site and extent of nutrient digestion in finishing beef heifers.

The objective of this study was to evaluate effects of increasing the inclusion of dry-rolled hybrid rye (HR) as a replacement for dry-rolled barley grain (DRB) on feed intake, ruminal fermentation, and the site and extent of nutrient digestion for finishing cattle. Eight ruminally and duodenally cannulated Hereford-cross heifers were used in a replicated 4 × 4 Latin square design with 21-d periods including 15 d of dietary adaptation and 6 d of data and sample collection. Dietary treatments included a control diet with 10.00% grass hay, 85.21% DRB, 4.51% of a vitamin and mineral supplement, and 0.28% of urea on a dry matter (DM) basis. Hybrid rye grain replaced 33%, 67%, or 100% of the DRB. Feed ingredients, feed refusals, ruminal pH, ruminal fluid, duodenal digesta, and fecal samples were collected from days 18 to 21 in each period. Data were analyzed using the Proc Glimmix procedure of SAS 9.4 (SAS Inst. Inc., Cary, NC) to evaluate the linear, quadratic, and cubic effects of increasing HR inclusion. Increasing HR inclusion as a substitute for DRB linearly decreased (P < 0.01) DM intake, linearly decreased mean ruminal pH (P < 0.01), and increased the duration (P < 0.01) and area (P = 0.02) that ruminal pH was < 5.5. There were no effects of HR inclusion on total short chain fatty acid and lactic acid concentrations in ruminal fluid. Likewise, the molar proportions of acetate and butyrate were not affected by HR inclusion. Propionate was cubically affected by HR inclusion (P = 0.02). Ruminal ash-free neutral detergent fiber (aNDFom) digestibility linearly increased (P = 0.03) with increasing HR, but there was no effect on ruminal starch digestibility averaging 71.1% (SEM = 3.611). Increasing HR inclusion linearly increased intestinal DM digestibility (% of flow to the duodenum; P = 0.03), tended to linearly increase intestinal digestibility of organic matter (P = 0.08), and tended to quadratically affect intestinal digestibility of aNDFom (P = 0.07). Increasing hybrid rye linearly increased apparent total tract DM, organic matter, crude protein, aNDFom, and starch digestibility (P ≤ 0.05). In addition, increasing HR inclusion linearly increased GE digestibility (P < 0.01) and the DE concentration (P < 0.01). Increasing the inclusion rate of HR grain as a substitute for DRB in finishing diets decreased DMI and increased risk for low ruminal pH, which may be influenced by greater digestible energy concentration arising from greater DM, OM, aNDFom, and starch digestibility.

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.

Hydrolysed poultry byproduct meal in extruded diets for cats

ABSTRACT Hydrolysed proteins have been shown to be potential ingredients in cat diets due to their high digestibility, presence of bioactive peptides, and relatively low antigenicity. The effects of the substitution of conventional low ash poultry byproduct meal (PBM) with hydrolysed poultry byproduct meal (HPM) as a protein source were evaluated in extruded cat diets. Five diets with similar nutrient contents were formulated: a control (CO) diet based on PBM and 4 diets with different inclusions of HPM (5%, 10%, 20%, and 30%, on an as-fed basis) replacing PBM as the protein source. The total tract apparent digestibility (CTTAD) of nutrients, faecal characteristics and microbial fermentation products, urine production and pH, nitrogen balance and urea renal excretion were evaluated using 30 healthy cats (15 males and 15 females; 4.18 ± 0.86 kg; 4.17 ± 1.38 years old), with 6 cats per diet in a complete randomised block design. When significant differences were found with the F test, the effects were evaluated by polynomial contrasts according to HPM inclusion (p < 0.05). The CTTADs of DM (89 ± 0.41%), CP (90 ± 0.36%), fat (93 ± 0.41%) and gross energy (90 ± 0.33%) were similar among treatments (p > 0.05). The faecal production, score, short-chain fatty acids and ammonia concentration were similar among treatments (p > 0.05). Isobutyric, isovaleric, valeric, and total branched-chain fatty acid contents increased quadratically (p < 0.05), with the highest level in the faeces of cats fed the diet with 20% HPM. Lactate concentration in faeces increased linearly with the inclusion of HPM (p < 0.05). Urine characteristics and urea renal excretion did not differ among treatments (p > 0.05). At 10% inclusion, HPM tended to increase the nitrogen retention of cats (p = 0.083), which may reflect the higher tryptophan, methionine, lysine, and available lysine contents of HPM in comparison to PBM. The inclusion of up to 30% HPM can be considered in cat formulations without affecting nutrient digestibility or faecal and urine characteristics. HPM tended to increase nitrogen retention and increased branched-chain fatty acids in faeces, aspects which deserves further studies.

Effect of forage quality and narasin inclusion on ruminal fermentation, nutrient intake, and total tract digestibility of Nellore steers.

The study aimed to evaluate the effects of forage quality and narasin inclusion on intake, digestibility, and ruminal fermentation of Nellore steers. Twenty-eight rumen-cannulated Nellore steers (initial body weight [BW] = 350 ± 32.4kg) were allocated to individual pens in a randomized complete block design, with 7 blocks, defined according to the fasting BW at the beginning of the experiment. The steers were randomly assigned within blocks to 1 of 4 experimental diets in 2 × 2 factorial arrangements, being the first-factor forage quality (MEDIUM = 81g of CP/kg of dry matter [DM], and HIGH = 153g of CP/kg of DM), and the second factor was the inclusion (N13 = diet plus 13mg/kg of DM of narasin) or not (N0) of narasin (Zimprova; Elanco Animal Health, São Paulo, Brazil). The experiment consisted of a 28-d period with 22 d for adaptation and the last 6d for data collection. No haylage quality × narasin interaction (P ≥ 0.68) was observed on DM and nutrient intake. Haylage quality affected (P ≤ 0.01) DM intake, with greater values observed for steers fed HIGH compared with MEDIUM haylage. There was an increase (P < 0.001) in OM, NDF, hemicellulose, and CP intake for steers consuming HIGH vs. MEDIUM haylage. Including N13 did not affect (P > 0.39) DM and nutrient intake of steers. No haylage quality × narasin interactions were detected (P ≥ 0.60) for total tract nutrient digestibility. However, steers fed with HIGH haylage showed an increase (P > 0.001) in DM and digestibility of all nutrients compared with MEDIUM. Steers fed a MEDIUM haylage had a greater (P < 0.01) proportion of acetate compared with steers fed HIGH during all evaluated hours. Steers fed HIGH haylage had a greater (P < 0.01) proportion of propionate at 0h compared with steers consuming MEDIUM, whereas at 12h, steers consuming MEDIUM hay had a greater (P < 0.01) proportion of propionate vs. HIGH haylage. A haylage quality × narasin and haylage quality × time of collection interactions were detected (P ≤ 0.03) for rumen ammonia concentration, which was reduced (P < 0.03) in N13 vs. N0 steers consuming HIGH haylage. Collectively, high-quality haylage allows increased consumption and digestibility, with more energy-efficient ruminal fermentation. In addition, narasin might be an important nutritional tool in forage-based diets to enhance the ruminal fermentation parameters of Bos indicus Nellore steers.