Diet Digestibility Research Articles

305 Dietary Carbohydrase Mixture Supplementation and Fiber Levels on Ileal Digestibility of Nutrients in Diets for Gestating Sows

Abstract Supplementation of multi-carbohydrase enzyme cocktails can increase nutrient digestibility of fibrous diets in grower pigs, particularly acting on dietary non-starch polysaccharides (NSP). Although NSP degrading enzymes are extensively used in sow diets, there is little data characterizing the NSP enzyme effects. Our previous work demonstrated a 10% increase in nutrient digestibility in diets fed to gestating sows. The objective of this study was to evaluate the effect of a carbohydrase mixture (CM) and dietary fiber level on standardized ileal digestibility (SID) of protein and amino acids (AA) and apparent ileal digestibility (AID) of NSP in gestation diets fed to pregnant sows. Ileal cannulas were placed in 12 gestating sows (Parity 0 to 2) who were allowed to recover for 1 week, then assigned to either a high (HF; 17.5% NDF) or low fiber (LF; 10% NDF) diet with one of 3 levels of CM supplementation (‘0’, ‘0.08’, and ‘0.10’%) or a nitrogen-free diet to determine ileal endogenous AA losses. Diets were corn-soybean meal based with soyhulls and corn DDGS as fiber sources and formulated to reflect industry-relevant diets. Thus, oil was included at 3% in HF to maintain similar formulated metabolizable energy content. Sows were fed once daily at 2.2 kg/d. Ileal digesta samples were collected for 12 h on 2 successive days following a 7-day adaptation period. At the end of digesta collection, sows were assigned a different diet in a new adaptation/digesta collection period. There were 5 collection periods for a total of 8 observations/diet. Digesta was analyzed for crude protein, amino acids, NSP, and titanium as the indigestible marker to determine AID and SID. There was no interaction between diet fiber level and CM supplementation. Carbohydrase mixture supplementation to gestating sow diets did not impact SID of crude protein and AA regardless of dietary fiber level. The SID of His, Ile, Lys, Phe, Thr, Trp, and Val were 3 to 6% lower (P < 0.09) in HF than LF independent of CM. There was no impact of fiber level on the average SID of amino acids in gestating sow diets which was 83.5%. Supplementation of CM did not impact AID of NSP components, but sows fed HF had greater AID of arabinose (LF: 26.5% vs HF: 40.6%), xylose (LF: 3.5% vs HF: 40.9%), and total NSP (LF: 25.9% vs HF: 40.0%) compared with sows fed LF (P < 0.05). Inclusion of CM in high fibrous gestating sow diets did not increase the SID of AA or AID of NSP, but a high fiber gestation diet reduced SID of AA. As such, differences in SID of AA should be considered when formulating high fibrous diets for gestating sows.

Growth Performance, Diet Digestibility, and Chemical Composition of Mealworm (Tenebrio molitor L.) Fed Agricultural By-Products.

Humanity's growing demand for animal protein exceeds the capacity of traditional protein sources to support growing livestock production. Insects offer promising partial substitutes, converting low-nutritional quality materials into high-value biomass. Hence, the bioconversion ability of Tenebrio molitor larvae was assessed by using three types of agricultural by-products (broccoli by-product, tigernut pulp, and grape pomace) at different inclusion levels (0%, 25%, 50%, and 100%) in a carbohydrate-based diet. Ten diets were formulated to assess their impact on the growth, diet digestibility, and nutritional composition of the larvae. For each treatment, eight replicates were employed: five for the growth-performance-digestibility trial and three for the complementary test of uric acid determination. The growth was influenced by the type of diet administered. The broccoli by-product resulted in higher larvae weight and a better feed conversion ratio. However, diets based solely on a single by-product (100%) compromised the productivity and diet digestibility. The larvae changed their nutritional composition depending on the rearing substrate, although the amino acid profile remained consistent. In conclusion, the studied by-products have the potential for use in T. molitor rearing as part of the diet but not as the exclusive ingredients, indicating promising opportunities for using agricultural by-products in T. molitor rearing and production.

Removal of sorghum stover from feed choices has no confounding effect on the quantity and quality of diets selected by group or individually fed sheep

ABSTRACT The study determined the effect of reducing dietary ingredients and group feeding on diet selection, nutrient intake and digestibility in choice-fed sheep. Three feeds comprising of veld hay (VH), sorghum stover (SS) and maize stover (MS) were offered ad-libitum while lucerne hay (LH) and bean straw (BS) were offered at restriction. Twelve sheep were allocated into three groups (i) group-fed in 3 sheep per pen, (ii) individually fed and, (iii) individually fed with SS exclusion. Sheep were rotated across the groups in four periods of 10 days. Diet selected, intake, refusals, spillages and faeces were monitored for seven days. The proportion of BS and LH consumed did not differ between group-fed and individually fed sheep with or without SS inclusion. Intake of MS and SS was lower in individually fed sheep while intake of VH was higher (p < 0.05). The proportion of BS and MS selected among individually fed sheep was similar with or without SS inclusion (p > 0.05). Diet selection was influenced by group feeding, but not the removal of SS. The scarcity of one dietary component may not result in the selection of undesired but available feeds if the quality is similar or poorer to the absent feed.

Fecal amylase-treated neutral detergent fiber and ash contents as independent variables can predict metabolizable energy and coefficient of energy digestibility of diets for growing pigs without dietary information

The objectives of the present study were to develop prediction equations for digestible energy (DE), metabolizable energy (ME), and coefficient of energy digestibility (ED) of swine diets using fecal nutrients as independent variables without dietary information and to validate the prediction equations. A total of 262 fecal samples obtained from growing pigs fed 27 diets in 4 experiments were used to develop prediction equations for DE, ME, and ED. These equations were validated using 95 fecal samples obtained from growing pigs fed 12 diets in an additional experiment. The diets were based mainly on corn, soybean meal, and other plant-originated feed ingredients. In the digestibility experiments, feces and urine were quantitatively collected using the marker-to-marker procedure. Diet and fecal samples were analyzed for dry matter (DM), crude protein, ash, and amylase-treated neutral detergent fiber (aNDF). The DE of the 27 diets ranged from 12,164 to 18,301 kJ/kg DM and ME of 24 diets ranged from 11,603 to 16,657 kJ/kg DM. Coefficients of ED for the 27 diets ranged from 0.667 to 0.919. Fecal ash was positively correlated with DE (r = 0.81; P < 0.001), ME (r = 0.66; P < 0.001), and coefficient of ED (r = 0.67; P < 0.001) whereas fecal aNDF was negatively correlated with DE (r = –0.66; P < 0.001), ME (r = –0.74; P < 0.001), and coefficient of ED (r = –0.67; P < 0.001). The prediction equations developed using fecal nutrients were: DE (kJ/kg DM) = 15,077 + (13.72 × ash) – (4.65 × aNDF) (R2 = 0.71; P < 0.001); ME (kJ/kg DM) = 17,067 + (6.54 × ash) – (7.56 × aNDF) (R2 = 0.63; P < 0.001); and coefficient of ED = 0.881 + (0.00037 × ash) – (0.00028 × aNDF) (R2 = 0.57; P < 0.001) where nutrients are expressed as g/kg DM. Based on the regression analysis for validation of the equations, the prediction equations for DE and coefficient of ED using only fecal aNDF did not have mean bias or linear bias. In conclusion, DE values, ME values, and coefficient of ED for swine diets are correlated with fecal ash and aNDF concentrations and the energy values can be predicted using fecal ash and aNDF concentrations without dietary information.

Leverage of Essential Oils on Faeces-Based Methane and Biogas Production in Dairy Cows

Currently, there is an ongoing intensive search for solutions that would effectively reduce greenhouse gas emissions (mainly methane) into the environment. From a practical point of view, it is important to reduce methane emissions from cows in such a way as to simultaneously trim emissions from the digestive system and increase its potential production from feces, which is intended as a substrate used in biogas plants. Such a solution would not only lower animal-based methane emissions but would also enable the production of fuel (in chemical form) with a high yield of methane from biogas, which would boost the economic benefits and reduce the use of fossil fuels. We tested the effect of administering an essential oil blend consisting of 5.5% oils and fats on methane and biogas production from dairy cow feces during fermentation. Three subsequent series (control and experimental) were conducted in dairy cows fed a total mixed ration (TMR) rich in brewer’s cereals and beet pulp, with 20% dry matter (DM) of the total diet. Cows from the experimental group received 20 g/cow/day of essential oil blend, namely a commercial additive (CA). The study showed that CA can increase the production of methane and biogas from dairy cow feces. It can be concluded that in the experimental groups, approx. 15.2% and 14.4% on a fresh matter basis and 11.7% and 10.9% on a dry matter basis more methane and biogas were generated compared to the control group, respectively. Therefore, it can be assumed that the use of CA in cow nutrition improved dietary digestibility, which increased the efficiency of the use of feces organic matter for biogas production.

Probiotic properties of Bacillus subtilis DG101 isolated from the traditional Japanese fermented food nattō.

Spore-forming probiotic bacteria offer interesting properties as they have an intrinsic high stability, and when consumed, they are able to survive the adverse conditions encountered during the transit thorough the host gastrointestinal (GI) tract. A traditional healthy food, nattō, exists in Japan consisting of soy fermented by the spore-forming bacterium Bacillus subtilis natto. The consumption of nattō is linked to many beneficial health effects, including the prevention of high blood pressure, osteoporosis, and cardiovascular-associated disease. We hypothesize that the bacterium B. subtilis natto plays a key role in the beneficial effects of nattō for humans. Here, we present the isolation of B. subtilis DG101 from nattō and its characterization as a novel spore-forming probiotic strain for human consumption. B. subtilis DG101 was non-hemolytic and showed high tolerance to lysozyme, low pH, bile salts, and a strong adherence ability to extracellular matrix proteins (i.e., fibronectin and collagen), demonstrating its potential application for competitive exclusion of pathogens. B. subtilis DG101 forms robust liquid and solid biofilms and expresses several extracellular enzymes with activity against food diet-associated macromolecules (i.e., proteins, lipids, and polysaccharides) that would be important to improve food diet digestion by the host. B. subtilis DG101 was able to grow in the presence of toxic metals (i.e., chromium, cadmium, and arsenic) and decreased their bioavailability, a feature that points to this probiotic as an interesting agent for bioremediation in cases of food and water poisoning with metals. In addition, B. subtilis DG101 was sensitive to antibiotics commonly used to treat infections in medical settings, and at the same time, it showed a potent antimicrobial effect against pathogenic bacteria and fungi. In mammalians (i.e., rats), B. subtilis DG101 colonized the GI tract, and improved the lipid and protein serum homeostasis of animals fed on the base of a normal- or a deficient-diet regime (dietary restriction). In the animal model for longevity studies, Caenorhabditis elegans, B. subtilis DG101 significantly increased the animal lifespan and prevented its age-related behavioral decay. Overall, these results demonstrate that B. subtilis DG101 is the key component of nattō with interesting probiotic properties to improve and protect human health.

Graduate Student Literature Review: System, plant, and animal factors controlling dietary pasture inclusion and their impact on ration formulation for dairy cows

Diet formulation in a pasture-based dairy system is a challenge as the quality and quantity of available pasture, which generally constitutes the base diet, is constantly changing. The objective of this paper is to cover a more in-depth review of the nutritional characteristics of pasture-based diets, identifying potential system, plant, and animal factors that condition pasture dietary inclusion in dairy cows. In practice, there is a wide diversity of pasture-based systems with predominant to minimal use of pasture requiring a more specific classification that potentially considers the amount and time of access to pasture, access to housing, length of grazing season, seasonality of calving, and level and method of supplementation. There are important differences in the nutritional quality between pasture species and even cultivars. However, under management practices that promote maintenance of pasture in a vegetative state as well as controlling the availability of pasture, it is possible to achieve high dry matter intakes (∼2.9%-3.4% of live weight) of pasture with moderate to high diet energy density, protein supply, and digestibility. The amount of pasture to include in the diet will depend on several factors, such as the type of production system, the cost of supplementary feeds, and the farmer's objectives, but inclusions of ∼40% to 50% of the diet seem to potentially reduce costs while apparently not limiting voluntary feed intake. Considering that there seems to be a continuum of intermediate management systems, a better understanding of the factors inherent to the feed ingredients used, as well as the use of nutrients by cows, and potential interactions between animal × system should be addressed in greater depth. This requires a meta-analysis approach, but given the diversity of the pasture-based system in practice, the existing information is highly fragmented. A clear definition of "subsystems" is necessary to direct the future research and development of mechanistic models.

Effects of Supplementation of a Mycotoxin Mitigation Feed Additive in Lactating Dairy Cows Fed Fusarium Mycotoxin-Contaminated Diet for an Extended Period.

Fusarium mycotoxins are inactivated by rumen flora; however, a certain amount can pass the rumen and reticulum or be converted into biological active metabolites. Limited scientific evidence is available on the impact and mitigation of Fusarium mycotoxins on dairy cows' performance and health, particularly when cows are exposed for an extended period (more than 2 months). The available information related to these mycotoxin effects on milk cheese-making parameters is also very poor. The objective of this study was to evaluate a commercially available mycotoxin mitigation product (MMP, i.e., TOXO® HP-R, Selko, Tilburg, The Netherlands) in lactating dairy cows fed a Fusarium mycotoxin-contaminated diet, and the repercussions on the dry matter intake, milk yield, milk quality, cheese-making traits and health status of cows. The MMP contains smectite clays, yeast cell walls and antioxidants. In the study, 36 lactating Holstein cows were grouped based on the number of days of producing milk, milk yield, body condition score and those randomly assigned to specific treatments. The study ran over 2 periods (March/May-May/July 2022). In each period, six animals/treatment were considered. The experimental periods consisted of 9 days of adaptation and 54 days of exposure. The physical activity, rumination time, daily milk production and milk quality were measured. The cows were fed once daily with the same total mixed ration (TMR) composition. The experimental groups consisted of a control (CTR) diet, with a TMR with low contamination, high moisture corn (HMC), and beet pulp; a mycotoxins (MTX) diet, with a TMR with highly contaminated HMC, and beet pulp; and an MTX diet supplemented with 100 g/cow/day of the mycotoxin mitigation product (MMP). The trial has shown that the use of MMP reduced the mycotoxin's negative effects on the milk yield and quality (protein, casein and lactose). The MTX diet had a lower milk yield and feed efficiency than the CTR and MMP HP-R diets. The MMP limited the negative effect of mycotoxin contamination on clotting parameters, mitigating the variations on some coagulation properties; however, the MMP inclusion tended to decrease the protein and apparent starch digestibility of the diet. These results provide a better understanding of mycotoxin risk on dairy cows' performances and milk quality. The inclusion of an MMP product mitigated some negative effects of the Fusarium mycotoxin contamination during this trial. The major effects were on the milk yield and quality in both the experimental periods. These results provide better insight on the effects of mycotoxins on the performance and quality of milk, as well as the cheese-making traits. Further analyses should be carried out to evaluate MMP's outcome on immune-metabolic responses and diet digestibility.

Digestibility and nitrogen balance of goats on high and low protein rations supplemented with a commercial tannin feed-additive

ABSTRACTDespite the increasing importance of goat production in response to high demand for their products and their relative robustness to environmental stressors, and in contrast to other ruminant species, little data is available on how tannin extract feeding affects their feed intake, nutrient digestion and nitrogen (N) metabolism. Therefore, a trial in Oman investigated the respective variables by using a commercial tannin feed additive. In a 4 (treatments) x 3 (periods) x 2 (animals) Youden square, two weaned Batinah bucks each were fed a high or low protein diet of Rhodes grass hay and crushed barley grain, with or without the addition of a chestnut and quebracho tannin extract at 2 g/kg metabolic weight. Feed offered, feed refused and faeces and urine excreted were quantified to determine diet digestibility, total N excretion, N retention and rumen microbial protein synthesis (MPS). Due to their young age and low live weight, feed intake of goats was relatively low. Crude protein level and tannin addition had no statistically significant effect on dry matter (DM) and N intake, DM digestibility, N excretion in faeces and urine, as well as MPS. In consequence, no benefit of tannin feeding could be confirmed for the goats’ N retention, irrespective of diet composition. These results indicate, on one hand, an effective neutralisation of the tested tannin extract along the gastrointestinal tract of goats, but on the other hand, that stimulation of MPS or N retention by tannins cannot be evidenced when diet components are present that simultaneously release energy and protein, as is the case with barley.

Solid-State Fermentation as Green Technology to Improve the Use of Plant Feedstuffs as Ingredients in Diets for European Sea Bass (Dicentrarchus labrax) Juveniles.

This study aimed to evaluate the utilization by juvenile European sea bass of a SSFed PF mixture with Aspergillus niger CECT 2088. A 22-day digestibility and a 50-day growth trial were performed testing four diets, including 20 or 40% of an unfermented or SSFed PF mixture (rapeseed, soybean, rice bran, and sunflower seed meals, 25% each). SSF of the PF added cellulase and β-glucosidase activity to the diets. Mycotoxin contamination was not detected in any of the experimental diets except for residual levels of zearalenone and deoxynivalenol (100 and 600 times lower than that established by the European Commission Recommendation-2006/576/EC). In diets including 20% PF, SSF did not affect growth but increased apparent digestibility coefficients of protein and energy, feed efficiency, and protein efficiency ratio. On the contrary, in diets including 40% PF, SSF decreased growth performance, feed intake, feed and protein efficiency, and diet digestibility. SSF decreased the intestinal amylase activity in the 40% SSFed diet, while total alkaline proteases decreased in the 20% and 40% SSFed diets. Hepatic amino acid catabolic enzyme activity was not modulated by SSF, and plasma total protein, cholesterol, and triglyceride levels were similar among dietary treatments. In conclusion, dietary inclusion of moderate levels of the SSFed PF, up to 20%, improves the overall feed utilization efficiency without negatively impacting European sea bass growth performance. The replacement of PF with the SSFed PF mixture may contribute to reducing the environmental footprint of aquaculture production.

Effects of dietary piperine supplementation on innate immunity, growth performance, feed utilization and intestinal morphology of olive flounder (Paralichthys olivaceus).

Piperine, the main bioactive component of black pepper (Piper nigrum) or long pepper (Piper longum), has anti-inflammatory, antifungal, and antibacterial properties. This study was carried out to evaluate the supplemental effects of piperine in olive flounder (Paralichthys olivaceus) diets. Six isonitrogenous and isolipidic diets were formulated to contain different levels of piperine at 0.00, 0.25, 0.50, 0.75, 1.00, and 2.00 g/kg (Con, P25, P50, P75, P100, and P200, respectively). Diets were randomly allocated to triplicate groups of fish (initial weight 27.6 ± 0.4 g, 30 fish/tank) and fed three times daily for 8 weeks. Results showed that dietary piperine significantly improved fish growth and feed utilization efficiency. The highest growth, including the highest Igf-1 mRNA expression, was observed in the P50 group, while P50 and P75 groups showed the highest protein efficiency ratio. Compared to the Con group piperine supplemented groups had significantly higher lysozyme activity, immunoglobulin level, and phagocytosis activities. Plasma cholesterol was significantly lower in fish fed P200 diet. Dry matter and protein digestibility were higher in P25, P50, and P75 groups than in Con group. Dietary piperine increased the intestinal villi length and goblet cell counts. In the challenge test against Edwardsiella tarda, all the groups supplemented with piperine showed higher cumulative survival compared to Con group. Therefore, these findings indicate that dietary piperine supplementation can improve growth performance, innate immunity, disease resistance, diet digestibility, and intestinal morphology of olive flounder. The optimum dietary piperine level seems to be approximately 0.5 g/kg for the fish.

Effect of hulled Cannabis sativa L. seeds in a home-made diet for adult dogs

Homemade diets integrated with functional ingredients may help to ensure that companion animals have a good life quality given the rise in their average lifespan. This study investigates the effects of a complete and well-balanced homemade diet supplemented with hulled hemp seeds. Twelve adult dogs divided into two groups: CTRL, fed the basal diet and HEMP, fed the diet integrated hulled Cannabis sativa L. seeds (4 g/100g of ration) were enrolled in the trial. The following samples were collected: (a) individual faecal samples to assess the diet digestibility through an indirect method of acid-insoluble ash; b) blood samples to evaluate the oxidative state through an OXI adsorbent test; and c) rectal swabs for intestinal microbiota analysis (alpha- and beta-diversity and taxonomy). The results reveal that with respect to the commercial diet used in this study, our homemade diet increased the total and protein digestibility (total: 53.97 ± 2.54% and 58.20 ± 2.58%; p < .030; protein: 70.54 ± 2.01% and 82.78 ± 5.35%; p < .001). The change in diet positively altered the microbiota structure and increased beta-diversity index significantly (p < .010). The hemp seeds significantly (p < .001) reduced the oxidative stress in the serum. This study highlights how hemp increases the body’s defences and that a homemade diet promotes diversity in the gut microbial population.

Distillers dried grains with soluble and enzyme inclusion in the diet effects broilers performance, intestinal health, and microbiota composition

This study tested the effect of distillers dried grains with soluble (DDGS) inclusion in a broiler diet, with or without supplementation of exogenous enzymes, on the microbiota composition, intestinal health, diet digestibility and performance. A total of 288 one-day-old chickens was assigned to 6 treatments (8 replicate of 6 birds each) according to a completely randomized design with a 3×2 factorial scheme with 3 DDGS levels (0, 7 and 14%) and 2 inclusions of exogenous enzymes (with or without a multicarbohydrase complex+phytase [MCPC]). The results exhibited that DDGS inclusion up to 14% did not impair broilers performance up to 28 d, however, DDGS-fed animals exhibited significant improvement with the MCPC supplementation. No effects of the enzymes in the ileal digestibility were found at 21 d. DDGS inclusion in the diet affected dry matter and gross energy digestibility. Broilers fed diets with MCPC were found to have less intestinal histological alteration thus better gut health. No effect of DDGS, enzyme or interaction of those were observed for intestinal permeability and in the serum inflammatory biomarker (calprotectin) at 7 and 28 d. The increase of DDGS percentage in the diet reduced the diversity of the ileal microbiota but increased the cecal microbiota diversity. The inclusion of DDGS showed positive effects on microbiota composition due to a reduction of Proteobacteria phylum in the ileum at 28d and a reduction in the presence of Enterococcaceae family in the ileum at 14 and 28d. The inclusion of MCPC complex might promote beneficial changes in the ileal and cecal microbiota due reduce of Proteobacteria, Bacillaceae and Enterobacteriaceae. The supplementation of xylanase, β-glucanase, arabinofuranosidase and phytase to a DDGS diet improves performance and intestinal health allowing the use of these subproduct in the poultry nutrition.

Digestibility and Palatability of the Diet and Intestinal Functionality of Dogs Fed a Blend of Yeast Cell Wall and Oregano Essential Oil.

Feed additives, such as prebiotics and essential oils, are used in pet foods and can affect digestibility, palatability, and intestinal functionality of dogs. The combined effects of yeast cell wall and oregano essential oil on apparent total tract digestibility (ATTD) and palatability of diet, intestinal fermentation products, and fecal microbiota in dogs were analyzed. Eighteen adult dogs were fed for 20 days with three dry extruded diets for adult dogs: control (without the additive), a diet containing 1.5 kg/ton of yeast cell wall and oregano essential oil (1.5YCO), and a diet containing 3.0 kg/ton of yeast cell wall and oregano essential oil (3.0YCO). The inclusion of both levels of YCO reduced the intake ratio. The addition of 3.0YCO reduced the ATTD of dry matter, compared to the control group (p < 0.05). There were greater putrescine and cadaverine concentrations and lower histamine and ammonia (p < 0.05) in the feces of dogs fed 3.0YCO. In addition, fecal odor of dogs fed YCO was less fetid than the control group (p < 0.05). There was greater fecal bacterial diversity in dogs fed with both dietary concentrations of YCO evaluated (p < 0.05). Dogs fed 1.5YCO and 3.0YCO showed higher relative abundance of Blautia and Faecalibacterium and lower abundance of Streptococcus (p < 0.05) in the feces, in comparison to the control group. Given the modulation of microorganisms considered beneficial and the lower fecal concentrations of histamine, phenols, and ammonia, the YCO blend resulted in indicators of improvement of intestinal functionality in dogs.

Gut microbiota of the small intestine as an antimicrobial barrier against foodborne pathogens: Impact of diet on the survival of S. Typhimurium and L. monocytogenes during in vitro digestion

The human gastrointestinal tract employs an assortment of chemical, enzymatic and immune barriers to impede pathogen colonization. An essential component of these barriers is the gut microbiota, which infers protection against ingested pathogens through its colonization resistance mechanisms. Specifically, the gut microbiota of the distal small intestine (ileum) renders a crucial line of defense, given that this location is regarded as an important interaction site. This study aimed to evaluate the impact of the ileal microbiota on the survival of the foodborne pathogens Salmonella enterica serotype Typhimurium and Listeria monocytogenes, utilizing an in vitro digestion model system. Moreover, the effect of diet on the gut microbiota colonization resistance mechanisms was assessed, by comparing a healthy (high fiber/low sugar) and a western diet (low fiber/high sugar). For S. Typhimurium, the results revealed that the digestion of a healthy diet led to a similar inactivation compared to the western diet, with the values of total log reduction being 0.83 and 0.82 log(CFU), respectively; yet the lack of readily accessible nutrients in the healthy diet combined with the acidic shock during gastric digestion caused the induction of stress tolerance to the pathogen. This resulted in increased pathogen survival in the presence of gut microbiota, with S. Typhimurium proliferating during the ileal phase with a maximum specific growth rate of 0.16 1/h. On the contrary, for L. monocytogenes, the healthy diet was associated with a greater inactivation than the western diet (total log reduction values: 3.08 and 1.30 log(CFU), respectively), which appeared strongly influenced by the encounter of the pathogen with the gut microbiota. Regarding the latter, the species Escherichia coli and Bacteroides thetaiotaomicron appeared to be the most prevalent in most cases. Finally, it was also demonstrated that the ileal microbiota colonization resistance mechanisms largely relied on competitive responses. The obtained knowledge of this research can contribute to the development and/or complementation of defensive strategies against pathogen infection, while also underlining the value of in vitro approaches.

Effect of green seaweed meal blend on feed quality and zootechnical performance in shrimp (Penaeus vannamei) juveniles

Aim of study: To evaluate a green seaweed meal in the diets of Penaeus vannamei juveniles, comprising Ulva spp., Caulerpa spp. and Enteromorpha spp. as a feed blend at inclusion levels at 4% and 8%. Area of study: Universidad Nacional Agraria La Molina, Lima, Perú. Material and methods: Analyses were conducted to determine the pellet quality through percentages of dry matter retention (DMR), protein loss and water absorption capacity; and to evaluate the effect of this seaweed meal in the digestibility and zootechnical shrimp performance. Three treatments (diets) were formulated to contain 0% (control diet), 4% (M4) and 8% (M8 of green seaweed meals (blend)), in isonitrogenous (crude protein; 300 g kg-1) and isocaloric (3.3 Mcal kg-1) diets. The shrimps were reared at a density of 286 juveniles m-3 for 29 days in a recirculating aquaculture system (RAS). Main results: Among the diets, M4 had the highest DMR value (97.06%), whereas M8 had highest water absorption capacity (185.48%) with lower % of protein loss between the treatments diets. No differences were observed in the zootechnical performance, except for survival (p&lt;0.05), with the M8 diet having highest mortality rate (44.4%) between the treatments diets. Research highlights: Incorporating 4% green seaweed meal in shrimp feed supported adequate growth and survival of juvenile P. vannamei with adequate DMR values, water absorption capacity, protein loss and high apparent dry matter digestibility and apparent digestibility of the reference diet.

Feeding Damascus goats humic or fulvic acid alone or in combination: in vitro and in vivo investigations on impacts on feed intake, ruminal fermentation parameters, and apparent nutrients digestibility.

In vitro and in vivo experiments were carried out to investigate the effects of the supplementation of different levels of humic and fulvic acids alone or their combination (2:1 ratio) on ruminal fermentation constituents, and nutrients digestibility in goats. The treatments in Exp. 1 were the following: (1) basal substrate (50% concentrate: 50% forage) was incubated humic at 0, 2, 4, and 6g/kg DM; (2) fulvic at 0, 1, 2, and 3g/kg DM; and (3) a combination of humic and fulvic (in a 2:1 ratio) at 0, 3, 6, and 9g/kg DM" of treatments. The results of Exp. 1 revealed that methane (CH4) production was linearly decreased (P < 0.001) upon increasing humic doses. Whereas, the combination of fulvic acid with humic acid resulted in a quadratic decrease (P < 0.001) in net CH4 production. Supplementing humic and fulvic acids, either separately or in combination, resulted in reduced (P < 0.05) ammonia nitrogen (NH3-N) and total volatile fatty acid (VFA) concentrations. In Exp. 2 to further examine the findings obtained in Exp. 1, forty Damascus non-lactating goats (2-3years of age and body weight 29 ± 1.5kg) were fed the same basal diet as in Exp. 1, plus one of four treatments. Treatments were the following: (1) control (no supplement); (2) basal diet plus 5g humic alone; (3) basal diet plus 2.5g fulvic alone, and (4) basal diet plus 7.5g their combination. Goats fed diets supplemented with humic acid, fulvic acid, either alone or in combination, increased concentrations of butyrate (P = 0.003), total VFA (P < 0.001), and improved (P < 0.001) digestibility of nutrients, but reduced (P < 0.001) ruminal NH3-N concentrations. In conclusion, applying humic and fulvic acids alone or in combination attenuated in vitro CH4 production, while improved intake and diet digestibility without adverse effect on rumen fermentation profiles in Damascus goats.

Effects of Bacillus subtilis C-3102 addition on nutrient digestibility, faecal characteristics, blood chemistry and faecal Lactobacilli spp., Enterococci spp., and Escherichia coli in healthy dogs

The benefits of probiotics for animal health are widely recognised. In this study, we investigated the effects of dietary supplementation with Bacillus subtilis C-3102 on diet digestibility, faecal characteristics, intestinal shedding of microbiota, and hematological characteristics in healthy dogs. Adult Golden Retriever dogs (n = 18) were divided into three groups: the control group (no B. subtilis), the BS1 group (1 × 109 CFU/g of B. subtilis), and the BS2 group (2 × 109 CFU/g of B. subtilis). Dogs were fed for a 30-day administration period, and total faeces were collected in the last five days. On the first and last days of the study, blood samples were taken to determine hematological characteristics. In addition, the dry matter content, faecal consistency score, faecal output, pH, ammonia level, and quantity of short- and branched-chain fatty acids (SCFAs and BCFAs) in faecal samples were also evaluated. Results revealed that the dry matter, fibre, organic matter, and protein digestibility coefficients were higher in BS1 and BS2 (p < 0.05) compared to the control. Lower pH and higher acetate, propionate, and isobutyrate levels were detected in BS1 and BS2 (p < 0.05). Lower ammonia levels and firmer stools were observed in BS2 (p < 0.001). The numbers of faecal enterococci and lactobacilli were higher in BS1 and BS2 (p < 0.05). Furthermore, B. subtilis increased the concentrations of WBCs, RBCs, and granulocytes in BS1 and BS2 (p < 0.05). Data in the present study suggest that dietary supplementation with B. subtilis improved faecal quality, enhanced nutrient digestibility, and contributed to the dogs’ gut health by reducing gut ammonia, increasing SCFAs, and improving the number of Lactobacillus and Enterococci. HIGHLIGHTS Probiotics are one of the most commonly used feed additives in dog food. Bacillus subtilis boosts the immunity and overall gastrointestinal health of companion animals. B. subtilis dietary supplementation improved dogs’ gut health, immunity, and digestibility of food. B. subtilis increased the concentration of WBCs, RBCs, and granulocytes. B. subtilis reduced gut ammonia and increased SCFAs and the number of lactobacilli and enterococci in faeces.

PROTEIN SPARING USING SAGO STARCH ON THE PERFORMANCE OF TIGER GROUPER, EPINEPHELUS FUSCOGUTTATUS ♀ × GIANT GROUPER, E. LANCEOLATUS ♂ HYBRID

Starch is an important non-protein energy source in the practical diets for fish and its optimal inclusion can maximise the use of dietary protein for growth. In the present study, a feeding trial was conducted to investigate the effects of protein sparing with carbohydrates on growth and diet digestibility in hybrid grouper (Epinephelus fuscoguttatus × E. lanceolatus). Diets were formulated with lowered levels of protein (50% to 45% and 40%) and increased levels of starch (20% to 25% and 30%). At the end of the feeding trial, growth performance and body indices (except for viscerosomatic index) were not significantly influenced (P &gt; 0.05) by the dietary treatments. In contrast, the whole-body proximate fish and liver compositions depended on the test diets. The dietary starch influences the haematological parameters, even though no clear trend was observed. Meanwhile, the apparent digestibility coefficient of protein and lipid was considered high in all experimental diets. Overall, the diet with protein level lowered to 45% and starch level increased to 30% performed as well as the control diet, indicating some ability of hybrid grouper to utilise sago starch as an energy source to spare protein.

Black soldier fly larvae oil as an alternative lipid source in diets for gilthead seabream (Sparus aurata) juveniles

The black soldier fly (Hermetia illucens, HI) is a promising insect species to be included in aquafeeds. HI larvae are rich in protein but also in fat, with a fatty acid profile dominated by saturated and medium-chain fatty acids. This study aimed to evaluate the replacement of vegetable oils (VO) with HI larvae oil (HIO) and its effects on growth, whole-body composition, nutrient retention, diet digestibility, and digestive enzyme activity. A control diet (HIO0, 45% crude protein, 18% lipids) was formulated to include 9.5% of a VO blend, and three other diets were formulated similar to the control but with the VO blend replaced at 42% (HIO42), 84% (HIO84), and 100% (HIO100). A growth trial was performed with triplicate groups of fish (initial body weight of 63 g) hand-fed to apparent visual satiation for 10 weeks. A digestibility trial was also performed simultaneously with triplicate groups of fish with similar initial body weights. Results indicate that the total replacement of VO mix with HIO did not affect growth performance, but feed efficiency and protein efficiency ratio linearly improved with the increase of HIO in the diets. No differences between groups were found in whole-body composition and protein and energy retention. There was a trend for protein and energy digestibility to linearly increase with dietary HIO inclusion. Lipid digestibility was not affected by diet composition, however, the apparent digestibility of saturated fatty acids increased and of unsaturated decreased with the increase of dietary HIO inclusion. Total proteases activity was higher in fish fed diet HIO84 and lipase activity followed a positive linear trend with the increase in dietary HIO content. Overall, present results indicate that gilthead seabream can effectively utilize HIO without compromising growth performance and digestibility while improving feed utilization efficiency, thus establishing its potential as an alternative lipid source for aquafeeds.