Digestible Energy Research Articles

Chlorella and vegetable oil inclusion in diets for growing rabbits: effects on growth, digestibility, plasma metabolites, and caecal fermentations and microbiota

The inclusion of microalgae in livestock diets has been shown to enhance animal productivity, immune response, and meat quality. However, the role of chlorella (Chlorella vulgaris) in growing rabbit nutrition has been scarcely explored, with available studies focusing on low inclusion levels (<1%) and their effects on rabbit growth and immune response. This study evaluated the growth performance, nutrient digestibility, plasma metabolites, caecal fermentative activity, and caecal microbiota composition of growing rabbits fed diets with different inclusion levels of chlorella and crude fat. A total of 648 mixed-sex Grimaud crossbred rabbits (33 d of age; 841 ± 140 g live weight) were fed 6 experimental diets (96 rabbits per diet for the growth trial) based on a bifactorial design with three dietary inclusion levels of chlorella (0%, 1%, and 2%) and two levels of crude fat (3% and 5%) obtained by the inclusion of soybean oil (1% and 3%, respectively). The trial lasted 38 days until slaughter. From 47 to 51 days of age, 72 rabbits (12 per diet) were submitted to a digestibility trial. At 51 days of age, samples of plasma and caecal content were collected from 36 rabbits (6 rabbit per diet) to analyse plasma metabolites, caecal fermentations, and caecal microbiota. Rabbit live weight at 71 days of age (2 700 g, on average), weight gain (48.8 g/d) and feed conversion ratio (3.27) were unaffected by chlorella inclusion, while feed conversion ratio improved (−5%; P < 0.001) with an increase of crude fat from 3% to 5%. The digestibility of ADF (23.2% vs. 20.9%; P < 0.05) and crude fat (83.8% vs. 85.6%; P < 0.01) improved with the inclusion of chlorella at 2%, as well as the digestibility of crude fat (82.4% vs. 86.9%; P < 0.001) and gross energy (57.3% vs. 58.7%; P < 0.001) with crude fat inclusion at 5%. Plasma non-esterified fatty acids decreased (−19%; P < 0.05) in diets with 5% crude fat. Neither chlorella nor crude fat inclusion levels affected other plasma metabolites, caecal fermentations, or caecal microbiota. Overall, the inclusion of chlorella up to 2% in diets for growing rabbits did not significantly affect diet nutritional value, animal performance, or caecal activity. On the other hand, increasing crude fat to 5% improved the overall feed efficiency.

The effect of protease supplementation in broiler chicken diets containing maize from different batches on growth performance and nutrient digestibility

Maize is the primary energy source in poultry diets. Nutritional and physical traits related to maize composition can affect nutrient utilization, as well as the efficacy of exogenous enzymes. A study was conducted to evaluate the effect of maize from different batches and protease supplementation on growth performance and ileal nutrient digestibility of broiler chickens from 1 to 40 days of age. A total of 1 920-day-old Ross 308 male chicks were assigned in a complete randomized design distributed into a 2 × 2 factorial arrangement comprising maize from two different batches (A and B) without and with protease (0 and 200 g/t), totaling 4 treatments and 12 replicates of 40 broiler chickens each. Experimental diets were divided into starter, grower I, grower II, and finisher phases. Both maize types were analyzed for nutritional composition, hardness, and structural differences in the starch granules via scanning electron microscopy. Feed intake, weight gain (WG), and feed conversion ratio (FCR) were evaluated. Ileal digesta was collected at 35 days to determine the apparent ileal digestibility (AID) of DM, CP, and ileal digestible energy (IDE). Hardness was higher in maize grains from batch A (P < 0.05), which may be associated with the denser and compact starch granules observed in electron microscopy. Broiler chickens fed maize from batch B and supplemented with protease showed greater WG and better FCR from 9 to 19 days (P < 0.05). From 1 to 40 days, birds fed the maize B diet had greater WG and lower FCR compared to those fed the maize A diet (P < 0.05). In the total period, protease supplementation reduced FCR (P < 0.01). No differences were found for AID of DM and CP, but broilers fed maize B diets had greater IDE (P < 0.05). In conclusion, although nutrient ileal digestibility was unaffected by treatments, the use of maize B led to superior growth performance and energy utilization due to its softer endosperm and starch composition, and protease supplementation reduced FCR and increased IDE regardless of maize batch.

Effect on Growth Performance and Nutritive Value of Cultivated Azolla filiculoides As An Alternative Feedstuff for Ruminant.

Azolla filiculoides is a tiny, free-floating aquatic fern and has a potential alternative protein and fibre source for ruminants, was investigated for its cultivation optimisation and feedstuff suitability. Study 1 was conducted to investigate the influence of different fertiliser types (control, broiler manure, sheep manure, cow manure) and concentrations (0.25 g/L-1.25 g/L) on the growth performance (fresh weight, doubling time, relative growth rate) and nutrient composition (dry matter, ash, crude protein, crude fibre, crude fat) of A. filiculoides. The optimised type of fertiliser and concentration in Study 1 were further adopted in Study 2 to evaluate the effect of different fertiliser processing methods on the growth performance, nutritive value and in vitro rumen digestibility of A. filiculoides upon cultivation. The findings in Study 1 showed that cultivation of A. filiculoides using sheep manure at the concentration of 1.00 g/L is the best resulted in the shortest doubling time (3 to 5 days) and produced fresh weight (FW), relative growth rate (RGR), crude protein (CP) and crude fibre (CF) at 132.2 g/m2, 0.32 g/g/day, 21.2% DM-1 and 14.4% DM-1, respectively. Furthermore, unprocessed sheep manure (T3) exhibited superior (p < 0.05) fresh weight, relative growth rate, nutrient composition and fibre components compared to the burned manure treatment (T2). In vitro digestibility analysis discovered that T3 achieved a 24-hour accumulated gas production of 86.9 mL DM-1, with in vitro dry matter digestibility (IVDMD), in vitro organic matter digestibility (IVOMD) and metabolisable energy (ME) of 82.9%, 43.7% and 5.8 MJ/kg DM, respectively. These findings suggest that Azolla filiculoides cultivation can be economically optimised using 1.00 g/L unprocessed sheep manure (fresh manure), potentially serving as a self-produced, nutritious feedstuff for ruminants.

An MINLP-based decision-making tool to help microbreweries improve energy efficiency and reduce carbon footprint through retrofits

Microbreweries have greater production costs per litre of beer compared to large breweries, as well as higher carbon footprints. Due to the range of different retrofit technologies available and the different capacities and configurations of microbreweries, it is not always clear what retrofits will improve operations. Therefore, this work proposes a novel mixed-integer nonlinear programming decision-making tool to be used by any microbrewery, that determines the technoeconomic feasibility and sizing of energy efficiency-improving retrofits, including solar and wind power, battery storage, anaerobic digestion, boiler type selection, heat integration by heat storage, and carbon capture via dual-function materials. The model was demonstrated on a real UK microbrewery case study. The model gave an optimal configuration of a 10 m3 anaerobic digester, 30 solar panels outputting 380 W each, an 800 W wind turbine and a 2.3 m3 heat storage tank, reducing annual operating costs by 62.9 % and carbon dioxide emissions by 77.1 % with a payback period of 8 years. The tool is designed to be flexible for use by any microbrewery in any location with any brewing recipe and allow the owner(s) to develop more profitable and sustainable microbreweries.Tweetable abstractMicrobreweries can implement mathematically optimised renewable energy, heat integration and anaerobic digestion to reduce operating costs by 62.9 % and carbon emissions by 77.1 %.

Energy and nutrient digestibility and effect of increasing the dietary inclusion of hull-less oats replacing wheat grain on growth performance of weanling pigs

Energy and nutrient digestibility and effect of increasing the dietary inclusion of hull-less oats replacing wheat grain on growth performance of weanling pigs

Comparison of the characteristics of small intestinal fluid from white-feathered and yellow-feathered broilers

The objective of this study was to compare the properties of small intestinal fluid (SIF) from white- and yellow-feathered broilers fed variable dietary CP to test the hypothesis that digestive enzymes sourced from the SIF of yellow-feathered broilers could serve as a viable alternative for preparing in vitro SIF specifically for white-feathered broilers. Ten Arbor Acres Plus broilers (32 days of age) and 20 Chinese yellow chickens (51 days of age) were fitted with jejunal cannulas and assigned to dietary treatments as follows: 1) white-feathered broilers (BW of 4.08 ± 0.39 kg) fed diet 1 with CP of 19.88 %, 2) yellow-feathered broilers (BW of 2.89 ± 0.27 kg) fed diet 1, and 3) yellow-feathered broilers (BW of 2.84 ± 0.20 kg) fed diet 2 with CP of 16.32 %. Each treatment contained 10 replicates with 1 broiler in each replicate. Digestive enzyme activities, ion concentrations, pH, 16 amino acid (AA, excluding Tyr and Trp) contents, molecular weight distribution (MWD) of protein, hydrolysis rates on wheat starch, corn starch, casein, and soybean protein concentrate, and in vitro digestible energy of corn, soybean meal, and corn gluten meal were evaluated for SIF. Activities of chymotrypsin and amylase, pH, concentrations (mg/mL) of total amino acid (TAA) and 13 AA (excluding Pro, Cys, and Glu), and hydrolysis rates in casein or soybean protein concentrate were greater (P < 0.05), whereas MWD of protein from 19 to 23 kDa was lower (P < 0.05) in the SIF of yellow compared to white-feathered broilers fed diet 1. Furthermore, activities of chymotrypsin and amylase, concentrations of Na+, and Cl−, MWD of protein from 15 to 18 kDa were greater, while concentrations of K+ were lower in the SIF of yellow-feathered broilers fed diet 2 compared to white feathered broilers fed diet 1. Activities of chymotrypsin and amylase, K+ concentration, pH, TAA and 13 AA (excluding Pro, Cys, and Glu), hydrolysis rates in casein or soybean protein concentrate increased (P < 0.05), while concentrations of Na+ and Cl− (P < 0.05) decreased with dietary CP in SIF from yellow-feathered broilers. This experiment demonstrated diet composition and breed modulate digestive enzyme activities, ions (Na+, K+, Cl−), pH, and AA concentrations in the SIF. Our findings revealed no substantial difference in the hydrolytic characteristics of SIF from white-feathered broilers fed diet 1 and yellow-feathered broilers fed diet 2. Consequently, it is feasible to use digestive enzymes extracted from the SIF of yellow-feathered broilers to prepare simulated SIF for in vitro digestion of white-feathered broilers.

Bioavailability of Supplemented Free Oleanolic Acid and Cyclodextrin-Oleanolic Acid in Growing Pigs, and Effects on Growth Performance, Nutrient Digestibility and Plasma Metabolites.

Oleanolic acid (OLA) has beneficial health effects in animals, but in vivo efficacy in monogastric animals is questioned due to its low bioavailability. To gain further insight on the nutritional effects of OLA it was administered as part of a diet. We investigated digestibility and plasma OLA in pigs and the associated influence on growth, organs, digestibility of nutrients and plasma biochemical profile. Twenty-four crossbred barrows (23.7 ± 1.0 kg BW) were assigned one of three treatments: Control (basal diet without OLA), OLA-1 (basal diet with 260 mg/free OLA) and OLA-2 (basal diet with 260 mg/kg cyclodextrin-OLA). Diets included chromium oxide to estimate digestibility. Blood samples were collected on day 14 for OLA analysis and feces on days 22-24 for determining digestibility. Pigs were slaughtered on day 31 (39.9 ± 2.43 kg BW) and their blood collected for analysis. Growth and organ weights were not affected (p > 0.05). OLA-1 decreased apparent total tract digestibility (ATTD) of energy (p < 0.05). OLA-2 increased ATTD of dry and organic matter compared with Control pigs (p < 0.05). OLA-1 increased plasma calcium and alkaline phosphatase (p < 0.05). Ileal digestibility of OLA was not affected (0.88), although OLA ATTD increased in OLA-1 compared to Control pigs (0.75 vs. 0.82; p < 0.05). OLA-1 and OLA-2 increased plasma OLA compared to Control pigs (p < 0.05 and p = 0.083). In conclusion, although the OLA was digested and absorbed, plasma concentration was low (4.29 µg/L), and pig growth, organs and plasma parameters were not affected.

Digestible energy and nutrient digestibility of full-fat soybean meal in adult and growing guinea pigs

Digestible energy and nutrient digestibility of full-fat soybean meal in adult and growing guinea pigs

Response of YPM x Ross 708 male broilers to diets containing varying inclusions of phytase, calcium butyrate, and bacitracin methylene disalicylate from 1 to 42 d of age–part 1: performance, processing yields, and nutrient digestibility

This 42-d study evaluated the effects of phytase, calcium butyrate (CB), and bacitracin methylene disalicylate 50 (BMD) on broiler performance, processing yields, and nutrient digestibility. Ross YPM x 708 male broilers (2,880 total) were distributed in 72 floor pens and assigned to 1 of 9 treatments (8 replicates/treatment) on d of hatch. This experiment was a 2 × 4 + 1 factorial arrangement, including 2 phytase concentrations (500 or 1,500 FTU/kg), 4 microbiota modulating feed additive groups (MMFA; none, CB (0.5 g/kg of diet), BMD (55 mg/kg of diet), or both CB and BMD), and a negative control without feed additives. Broiler performance (d 14, 28, and 42), apparent ileal nutrient digestibility (d 28 and 42), and processing yields (d 43) were determined. Day 14 BW increased with BMD inclusion compared to CB and no MMFA in the 1,500 FTU/kg group but BW were similar between all MMFA combined with 500 FTU/kg (P ≤ 0.05). Supplementing BMD increased d 28 BW and reduced d 1 to 28 feed conversion ratio compared to CB and no MMFA (main effect, P ≤ 0.05). Day 42 BW varied depending on dietary phytase concentrations. When diets contained 500 FTU/kg, broilers fed both CB and BMD had a higher BW than broilers fed only CB. Whereas when the inclusion of phytase was increased to 1,500 FTU/kg, broilers fed diets with only BMD or both CB and BMD had higher BW than broilers fed diets with no MMFA (P ≤ 0.05). Phytase concentrations at 1,500 FTU/kg increased (P ≤ 0.05) digestibility of fat (main effect, d 42), phosphorus (d 28 and 42), and apparent ileal digestible energy (main effect, d 42) compared to 500 FTU/kg. In this study, dietary BMD improved broiler growth compared to CB and no MMFA. However, these observed differences between CB and BMD were dependent on dietary phytase concentrations.

Dehydrated Brewery Residue (DBR) can reduce the cost of rabbit production in Brazil, but affects performance, blood nutrients, and carcass characteristics

The study aimed to determine the chemical composition, apparent digestibility of dry matter, energy, and nutrients of Dehydrated Brewery Residue (DBR) for New Zealand White rabbits, as well as evaluate performance, biochemical and immunological blood parameters, carcass characteristics, and meat quality. Two experiments were carried out: digestibility and performance, both in a completely randomized design. In the digestibility experiment, 20 animals of mixed sexes were used, from 45 to 60 days of age, which consumed reference feed (RF) or test feed (TF - 70% RF + 30% DBR). In the performance experiment, 50 mixed-sex animals were used from 31 to 70 days of age. For digestibility, bromatological analyses were made of total dry matter (DM), crude protein (CP), crude fiber (CF), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), mineral matter (MM), organic matter (OM), calcium (Ca), phosphorus (P), gross energy (GE), hemicellulose, cellulose and lignin from samples of feces, feed (RF and TF) and experimental feed (DBR). In terms of performance, the treatments were the basal feed (BF) + four TF, made up of increasing levels of DBR inclusion (10, 20, 30, and 40%). Overall, the apparent digestibility coefficient (ADC) of DM was 64.68 ±7.91%, while the ADC of GE and CP were 67.39 ±7.79% and 80.64 ±8.99%, respectively, resulting in digestible energy and digestible protein contents of 3,081 ±356 kcal/kg and 17.97 ±2.00%. There was a linear reduction (P&lt;0.05) in the final weight, daily weight gain, and daily feed intake, but there was a linear reduction in production costs (P&lt;0.05) for both the 31- to 50-day phase and the 31- to 70-day phase. Circulating levels of calcium (P=0.013) and phosphorus (P=0.019) responded in a linear decreasing pattern to the experimental feeds. The same response was observed for slaughter weight, hot and cold carcass weight, yield of skin, head, commercial cuts, and relative weight of edible organs, as well as meat quality, in which the loss of water on thawing (P=0.004) and shear force (P=0.005) indicated less juiciness and less tenderness in the meat. Levels of 10 to 40% DBR in feed for rabbits from 31 to 70 days of age mitigate production costs, but result in a worsening of performance and reduce circulating levels of calcium and phosphorus, reduce carcass weight, commercial cuts, and edible organs, as well as increasing water loss on thawing, and reducing meat tenderness.

Effect of coated-benzoic acid on growth performance, immunity, and intestinal functions in weaned pigs challenged by enterotoxigenic Escherichia coli.

Benzoic acid (BA) could be added to the diets of weaned pigs to prevent diarrhea due to its antibacterial function. However, BA may be absorbed or decomposed before it can reach the hindgut. This study was conducted to explore the effect of a novel coated benzoic acid (CBA) on growth performance, immunity, and intestinal barrier functions in weaned pigs upon enterotoxigenic Escherichia coli (ETEC) challenge. In a 21d experiment, 32 piglets were randomly assigned to 4 treatments: (1) a basal diet (CON), (2) CON added with CBA at 3 g/kg (CBA); (3) CON and challenged by ETEC (ECON); (4) CON added with CBA at 3 g/kg and challenged by ETEC (ECON). On d 22, all piglets were euthanised to obtain samples. Dietary CBA supplementation elevated the average daily gain (ADG) of the ETEC-challenged pigs (p < 0.05). CBA also improved the digestibility of dry matter, gross energy, and ash (p < 0.05). Moreover, CBA elevated the ratio of blood basophil and the serum concentration of total cholesterol of the ETEC challenged pigs (p < 0.05). Importantly, CBA increased the serum concentrations of immunoglobulin A (IgA), IgG, and IgM (p < 0.05). CBA not only decreased the crypt depth but also increased the ratio of villus height to crypt depth (V:C) in the jejunum and ileum (p < 0.05). Moreover, CBA increased the activities of jejunal and ileal sucrase, and the activities of duodenal and ileal maltase (p < 0.05). Importantly, CBA elevated the expression levels of critical functional genes such as the claudin-1, occluding, glucose transporter-2 (GLUT2), and sodium/glucose cotransporter-1 (SGLT-1) in the jejunal epithelium upon ETEC challenge (p < 0.05). Additionally, CBA increased the abundances of total bacteria and Bacillus, and increased the concentrations of volatile fatty acids (acetic acid, propanoic acid, and butyric acid) in cecum (p < 0.05). These results suggested a beneficial role for CBA in alleviating intestinal injury in weaned pigs following ETEC challenge. Such effects may be tightly associated with elevated immunity and improved intestinal epithelium functions and microbiota.

Socially Acceptable Feed Formulations May Impact the Voluntary Feed Intake and Growth, but Not Robustness of Nile Tilapia (Oreochromis niloticus)

Society is becoming more demanding with aquaculture’s environmental footprint and animal wellbeing. In order to potentially mitigate these concerns, feed formulations could be based on eco-efficient (circular economy-driven) or organic ingredients. This study aimed to investigate the growth performance, feed utilization, and health status of juvenile Nile tilapia (Oreochromis niloticus) when fed with such feeds. The growth trial lasted for 8 weeks, and fish had an initial weight of 31.0 ± 0.5 g (mean ± SD). Fish were fed until visual satiation, in quadruplicate, with one of three isonitrogenous and isoenergetic experimental feeds: a commercial-like feed without fishmeal (PD), a diet based on ingredients compatible with organic certification (ORG), or a feed formulated using circular economy-driven subproducts and emergent ingredients (ECO). Fish fed ECO showed a tendency for decreased feed intake, while ORG fish significantly reduced their intake compared to those fed PD. Consequently, fish fed ECO (62.7 ± 5.4 g) exhibited almost half the growth than those fed PD (107.8 ± 6.1 g), while ORG fish almost did not increase their weight (32.7 ± 1.3 g). ECO and ORG diets had a lower digestibility for protein, lipid, and energy when compared to PD. Feed utilization of fish fed ECO or ORG was also lower than those fed PD. From the health-related genes analyzed, only glutathione reductase (gsr) showed statistically significant differences, being more expressed in fish-fed ECO than those fed PD. Thus, even when such novel formulations induced extreme effects on voluntary feed intake, their impact was noted only in fish growth, but not in robustness.

Interaction of Wheat Bran Particle Size and Stimbiotic Supplementation on Growth Performance and Gut Health Parameters in Broilers.

A 42-day study was conducted with 720-day-old Cobb male broiler chicks allocated to treatments in a 3 × 2 factorial, with the factors as wheat bran (WB) inclusion (no WB, 50 g/kg coarse WB, or 50 g/kg fine WB) and stimbiotic (STB) supplementation in corn-based diets. The inclusion of WB (p < 0.05) or STB supplementation (p < 0.05) increased the FCR and feed intake in the day 0-10 phase. During the day 0-28 phase, coarse-WB inclusion increased (p < 0.05) the FCR, compared to fine WB or diets without WB. In the day 0-42 phase, WB marginally decreased weight gain in diets without STB supplementation, but the STB-supplemented diet, weight gain was greater (p < 0.05) the diet with fine WB compared with diets with coarse WB. Fine-WB inclusion increased the ileal nitrogen and energy digestibility determined at day 18 compared to coarse WB or diets without WB. Supplementation with STB (p < 0.05) or fine WB (p < 0.05) inclusion increased the villi height compared to diets without STB supplementation or coarse WB, or the diet without WB. Coarse or fine WB decreased (p < 0.05) cecal branched-chain fatty acids compared to diets without WB. In conclusion, stimbiotic supplementation to fine WB improved the performance and nutrient digestibility of broilers compared to coarse WB with no effects on the caeca total SCFA concentration.

PSI-26 Effects of particle size and enzyme supplementation on the energy value of field peas fed to growing pigs

Abstract An experiment was conducted to determine if particle size and enzyme supplementation affects the digestible energy (DE), metabolizable energy (ME), and net energy (NE) contents in field peas fed to growing pigs. Male weaned pigs [n = 30; TN70 × TN Tempo; body weight (BW) = 16.5 ± 0.4 kg] were assigned to 1 of 5 dietary treatments: 4 consisting of 50% peas and a corn-soybean meal basal diet. The experiment was carried out as a completely randomized design with treatments arranged in a 2 × 2 factorial design, based on two particle sizes (500μm, 700μm) and two levels of carbohydrase supplementation (0 g/mt, 1,000 g/mt) to give 6 replicates per treatment. Diets were formulated to meet or exceed NRC (2012) requirements. The study was carried out in 3 consecutive periods, each consisting of 15 d; the first 10 d were for adaptation, followed by 5 d of total fecal and urine collection (marker to marker procedure) to calculate DE and ME of diets. The energy content of peas was determined using the difference method. Data were analyzed using the MIXED procedure of SAS. The model included the particle size, enzyme supplementation, and their interaction as a fixed effect. The period was included as a random effect. Least squares means for each treatment were adjusted using Tukey post-hoc test. Dry matter (DM), acid detergent fiber, neutral detergent fiber, gross energy, starch, ash, crude protein, and ether extract contents were analyzed to allow for the prediction of NE content of peas. There were no interactions between particle size and enzyme supplementation on dietary energy values. Also, no main effects of particle size and enzyme supplementation were observed. The average DE, ME, and predicted NE contents for peas were determined to be 3,848, 3,735, and 2,691 kcal/kg DM, respectively. In conclusion, enzyme supplementation and particle size did not influence the DE, ME, and NE contents of the peas.

PSIX-5 Performance of black soldier fly larvae meal as secondary protein sources in extruded dog diets

Abstract Black soldier fly larvae meal (BSFL) has gained market exposure with ties to sustainability and novelty. Graded inclusions of BSFL were assessed for nutrient digestibility, stool quality, and palatability in adult dogs. The BSFL was included at 0%, 5% and 10% in chicken-based extruded dog diets (formulated to 22% crude protein, 13% crude fat, 3% crude fiber). The study was approved by the facility’s Institutional Animal Care and Use Committee. A standard 2-bowl palatability test over a 2-d period was executed (n = 30 dogs each) to determine intake ratios between diets (0% vs. 5%, 0% vs. 10%, and 5% vs. 10%). Total tract nutrient digestibility was evaluated (n = 6 dogs per diet) with 5 d acclimation followed by 5 d total fecal collection. Stool quality was evaluated on a 1 to 5 scale. Palatability data were analyzed using paired t-test. To test for mean differences in digestibility and stool quality outcomes between 0%, 5%, and 10% BSFL dogs, we applied the Kruskal-Wallis test. Statistical significance was set at 5% type 1 error rate. Dry matter, protein, fat, and energy digestibility, and stool quality were similar between all diets (P &amp;gt; 0.05). Palatability was improved (P &amp;lt; 0.05) with inclusion of BSFL (i.e., preference for 5% and 10% vs. 0% inclusion) and improved (P &amp;lt; 0.05) at 10% vs. 5% inclusion. The BSFL tested showed merit as a palatable ingredient source that maintains stool quality and digestibility in adult dogs.

PSII-17 Effect of dietary β-mannanase supplementation on energy and nutrient utilization in diets fed to broiler chickens: A meta-analysis

Abstract Beta-mannan (β-mannan) is a polysaccharide composed of repeating units of mannose, galactose, and glucose. The increased amount of β-mannan is present in various plant protein sources such as soybean meal, palm kernel meal, copra meal, and guar meal. β-mannan is considered an antinutritional factor for non-ruminant animals. Endo-β-mannanase enzymes are endo-hydrolases that can cleave the internal glycosidic bonds of the mannan backbone. As a result, β-mannanase is used to break down β-mannan in animal feeds, thereby aiming to reduce its potential anti-nutritional effects. Previous research has demonstrated that dietary β-mannanase supplementation improves energy and nutrient utilization in broiler diets possibly by decreasing digesta viscosity in the gastrointestinal tract. However, results from previous studies have been inconsistent, mainly due to variable experimental conditions including animals, experimental design, and environment. Meta-analysis is a useful method to comprehensively evaluate and integrate various results from previous studies, thereby providing reliable and practical insights. Therefore, the objective of this study was to conduct the meta-analysis to evaluate the effect of dietary β-mannanase supplementation on digesta viscosity, and energy and nutrient utilization in diets for broiler chickens. Through an extensive literature search conducted on Scopus, PubMed, Web of Science, and Google Scholar between January 2003 and December 2023, we identified 10 eligible studies. The meta-analysis was performed using the “metafor” package in R software version 4.1.3. (R Core Team, 2023), and the standardized mean difference (SMD) and its 95% confidence interval (CI) were calculated using the random effect model. The results revealed that dietary β-mannanase supplementation increased apparent total tract retention (ATTR) of dry matter (SMD = 1.84; 95% CI: 0.46 to 3.21; P = 0.016), gross energy (SMD = 2.16; 95% CI: 1.19 to 3.12; P = 0.001), and nitrogen-corrected apparent metabolizable energy (AMEn) in broiler diets (SMD = 3.38; 95% CI: 1.63 to 5.14; P = 0.002; Table 1). Moreover, dietary β-mannanase supplementation increased apparent ileal digestibility (AID) of gross energy (SMD = 6.65; 95% CI: 3.78 to 9.53; P = 0.002) and nitrogen (SMD = 1.41; 95% CI: 0.55 to 2.27; P = 0.006) in broiler diets (Figures 1 and 2). Finally, digesta viscosity (SMD = -3.35; 95% CI: -4.69 to -2.02; P &amp;lt; 0.001) in broiler chickens was decreased by dietary β-mannanase supplementation. In conclusion, the current meta-analysis indicates that dietary β-mannanase supplementation improves the overall utilization of energy and nutrients in diets with decreasing digesta viscosity in broiler chickens.

PSLBII-30 The effect of different soybean meal batches and protease supplementation on nutrient utilization by broiler chickens

Abstract Soybean meal (SBM) is the major protein source in broiler chicken diets. However, the thermal processing of SBM may have an impact on its protein quality, reducing its solubility when over-processed. In this context, the use of exogenous protease may reduce the negative effects that the over-processing of SBM may have on protein digestibility in broiler chickens. The present study investigated two batches of SBM in broiler chicken diets supplemented or not with protease. One-d-old male Cobb 500 (n = 360) were randomly distributed in a 2 x 2 factorial arrangement (SBM batches: A and B; Protease inclusion: 0 and 50 g/t of diet). SBM protein quality was evaluated through crude protein (CP), KOH solubility, and urease activity test (UA) in batches A and B. Scanning electron microscopy was used to visualize the structural organization of particles from SBM A and B. On d 26, ileal digesta content was collected from 6 broiler chickens that were euthanized to determine the apparent ileal digestibility (AID) of dry matter (DM), crude protein (CP), and ileal digestible energy (IDE). Data obtained were submitted to ANOVA and means were compared by Tukey test with a significance declared of 5% using the GLM procedure on R Software. Protein quality assessment demonstrated KOH solubility of 85% and 75% for SBM from batches A and B, respectively. For UA analysis, SBM batch A presented 0.09 and batch B of 0.01 mg N/g (Table 1). Microscopy images emphasized visual differences in particles from batches A and B. In SBM particles from batch A, disorganized cluster structures and asymmetric pores were observed, whereas in the SBM particles from batch B, insignificant pores and large cluster aggregates were visualized in a denser structure (Figure 1). The SBM batch B presented decreased AID of DM, CP, and IDE (P &amp;lt; 0.05). Protease supplementation improved the AID of CP (P &amp;lt; 0.05) in broilers at 26 d of age, regardless of SBM batches, but no effect was observed for DM and IDE (P &amp;gt; 0.05; Table 2). In conclusion, SBM from batch A had greater values of KOH solubility and UA, suggesting an appropriate thermal process, and ensuring protein quality, which is demonstrated through improvement in nutrient utilization by broiler chickens. The use of 50 g of exogenous protease per t of diet improved the ileal digestibility of CP, regardless of SBM batches.

PSI-29 Enhancing growth performance and reducing environmental impact with dietary protease supplementation in growing pigs fed high- and low-density diets

Abstract Exogenous protease has emerged as a promising solution for enhancing protein digestion and utilization in animal diets, offering potential benefits for both animal performance and environmental impact mitigation in pig farming. In a 6-wk trial involving 140 growing pigs [initial body weight (BW) = 24.10 ± 1.66 kg], the effects of dietary protease supplementation on growth performance, nutrient digestibility, and noxious gas emission were investigated. Pigs were randomly assigned to one of four dietary treatments in a 2 x 2 factorial design with two levels of nutrient density and 0 or 125 g/ton supplementation of protease. The pigs were blocked by BW and housed in 28 pens with each pen consisting of 5 pigs (3 barrows and 2 gilts). The experimental design employed a randomized complete block design with 7 replicate pens per treatment. The data were analyzed using two-way ANOVA, with differences between means assessed using Tukey’s test (P &amp;lt; 0.05). Results revealed no significant interaction (P &amp;gt; 0.05) between nutrient density and protease supplementation concerning growth performance, nutrient digestibility, and noxious gas emission. Pigs subjected to high-density diets exhibited greater (P &amp;lt; 0.05) average daily gain (ADG) and gain-to-feed ratio (G:F) compared with those on low-density diets. While protease supplementation did not impact ADG and average daily feed intake (ADFI), there was a tendency towards reduced (P = 0.08) G:F throughout the 6-wk period. Pigs fed high-density diets demonstrated significantly greater (P &amp;lt; 0.05) apparent total tract digestibility (ATTD) of gross energy (GE) compared with their counterparts on low-density diets. Furthermore, the inclusion of protease significantly increased (P &amp;lt; 0.05) ATTD of GE. However, no discernible differences were noted among diets regarding the ATTD of dry matter and nitrogen. Regarding noxious gas emission, protease supplementation did not significantly affect total mercaptans and hydrogen sulfide (H2S) emission. Nonetheless, there was a notable trend towards reduced (P = 0.06) ammonia gas (NH3) emission with protease inclusion. Similarly, nutrient density did not exhibit a significant effect (P &amp;gt; 0.05) on noxious gas emission. In conclusion, the results of the study underscore the importance of nutrient density and protease supplementation in optimizing pig performance and environmental sustainability in swine production systems. Further research is warranted to elucidate the underlying mechanisms and refine strategies for maximizing the benefits of these dietary interventions.

448 Interactive effects of extrusion and particle size reduction of corn on metabolizable energy by weanling pigs

Abstract The objective was to test the hypothesis that there are interactive effects of extrusion and reduction of the particle size of corn on apparent total tract digestibility (ATTD) of gross energy (GE) and digestible energy (DE) and metabolizable energy (ME) when fed to weanling pigs. Six corn-based diets were arranged in a 3 × 2 factorial with 3 particle sizes of corn (i.e., 700, 500, or 300 μm) and two forms (i.e., meal or extruded corn). The daily feed allowance was limited to 3.0 times the energy requirement for maintenance and pigs had free access to water. Pigs [n = 48; initial body weight (BW) = 12.8 kg; SD = 1.32) were housed in metabolism crates and allotted to the 6 diets using a randomized complete block design with two blocks. Fecal and urine samples were quantitatively collected for 4 d following 5 d of adaptation. The statistical model included diet as fixed effect and block as random effect. Contrast coefficients were used to determine effects of extrusion, linear effects of particle size, and the interaction. Results indicated that the ATTD of GE and DE and ME in corn increased by reducing the particle size of corn only if corn was in a meal form, but that was not the case for extruded corn (interaction; P &amp;lt; 0.001; Table 1). Regardless of particle size, the ATTD of GE and DE and ME in corn were increased (P &amp;lt; 0.001) by extrusion. In conclusion, reducing particle size of corn had a positive impact on energy digestibility in non-extruded corn. Regardless of particle size, extrusion of corn increased energy digestibility and DE and ME, which is likely a result of starch gelatinization in extruded corn. However, the effects of reducing particle size and extrusion were not additive, which indicates that it is not necessary to grind corn to 500 or 300 μm before extrusion.

380 Diet protein concentration does not influence dietary net energy by group housed growing pigs offered ad libitum access to feed

Abstract The objective was to test the hypothesis that net energy (NE) of diets is not increased by reducing soybean meal (SBM) and increasing crystalline amino acids (CAA) in diets fed to group-housed pigs on an ad libitum basis. Two “normal protein” diets with 17 and 14% crude protein (CP) were formulated. One diet was based on corn, SBM, and no CAA and the other diet was based on corn, SBM, and crystalline Lys, Met, and Thr. Four additional diets containing 13, 12, 11, or 10% CP were formulated by reducing SBM and increasing crystalline Lys, Met, Thr, Trp, Val, and Phe. Growing pigs (n = 24; initial body weight = 29.9 ± 2.4 kg) were randomly allocated to 6 calorimeter chambers with 4 pigs per chamber. The 6 chambers were allotted to the six diets using a 6 × 6 Latin square design with six 15-d periods providing 6 replicate chambers per diet. Pigs had ad libitum access to diets throughout the experiment except during the fasting periods. Consumption of O2 and production of CO2 and CH4 were measured, and fecal and urine samples were collected for 6 d after 7 d of adaptation. Fasting heat production (FHP) was determined for 12 h following a 24 h fasting period. Diets, fecal samples, and lyophilized urine samples were analyzed for gross energy (GE) and N. Data were analyzed using contrasts statements to determine linear and quadratic effects of reducing dietary protein. Results indicated that feed intake, fecal and urine GE output, the apparent total tract digestibility (ATTD) of dry matter and GE, total heat production (THP), FHP, and retained energy were not different between pigs fed the 17 and the 14% CP diets (Table 1). The respiratory quotient (RQ) of pigs fed the 17% CP diet was less (P = 0.045) compared with the 14% CP diet. Digestible energy (DE) and metabolizable energy (ME) in the 17% CP diet were greater (P &amp;lt; 0.05) than in the 14% CP diet, but NE was not different between these 2 diets. Feed intake, GE intake, and fecal GE output of pigs were linearly (P = 0.044) increased by reducing CP in diets, but reducing diet CP did not affect ATTD of dry matter or GE or urine GE excretion. Total heat production, FHP, retained energy, and DE, ME, and NE were also not affected by reducing CP in diets. In conclusion, reducing CP of diets for pigs by reducing SBM and increasing CAA did not increase NE of the diet when fed to group-housed pigs on an ad libitum basis, and dietary CP does not appear to influence diet NE.