Effect of bacterial protein meal grown on natural gas on growth performance and carcass traits of pigs

Dietary inclusion of methanotrophic microbial cell-derived protein in the early post-weaning period sustains growth performance and intestinal health of weaner piglets

The global demand for sustainably produced protein feeds for animal production is increasing. Methanotrophic bacteria grow on methane and convert it into microbial cell protein (MCP) that has been shown to have high nutritive value for growing pigs. The present aimed to investigate how increasing amounts of MCP in diets fed during the first 15 days after weaning affect the growth performance of piglets from weaning until day 43 postweaning. Furthermore, the effect of MCP on intestinal morphology and histopathology was assessed on day 15 after weaning. During seven consecutive weeks, approximately 480 piglets were recruited for the experiment per batch. The piglets were divided into four groups and housed in eight double pens with 60 piglets per pen. The piglets were fed one of four experimental diets with 0, 3, 6, or 10% of MCP included at the expense of fishmeal and subsequently potato protein for the first 15 days postweaning. Thereafter, all pigs were fed commercial weaner diets in two phases (days 16-30 and days 31-43) until day 43 postweaning. All diets were without medicinal zinc. Feed intake and growth were registered on double pen level during all three phases. On day 15 after weaning, 10 piglets per treatment were randomly selected, autopsied, and sampled for intestinal morphology and histopathology. Daily gain during the first 15 days postweaning tended (P = 0.09) to be affected by the inclusion of MCP in the weaning diet being lowest in the group fed 10% MCP. Treatment did not affect daily feed intake; however, Feed Conversion Ratio (FCR) was significantly affected (P = 0.003) showing the highest FCR in piglets fed 10% MCP. Growth performance was not affected by the experimental treatment during the following phases. In the small intestine, villous height tended (P = 0.09) to show a quadratic response to level of MCP in the diet with the longest villi observed after feeding 6% MCP. Dietary treatment did not affect crypt depth. The villous height to crypt depth (VC) ratio showed a quadratic response to increased dietary inclusion of MCP (P = 0.02) with piglets fed 6% MCP having the highest VC ratio. In conclusion, this study demonstrated that MCP could constitute 6% of diets as-fed (22% of total CP), at the expense of fishmeal and potato protein, for newly weaned piglets without negative effects on growth rates and FCR. The inclusion of MCP in diets for newly weaned piglets could be part of improving the sustainability of pig production.

A Natural Gas Fermentation Bacterial Meal (FeedKind®) as a Functional Alternative Ingredient for Fishmeal in Diet of Largemouth Bass, Micropterus salmoides

A 10-week growth study was conducted to evaluate the effect of a natural gas fermentation bacterial meal (FeedKind^®, FK) as a fishmeal (FM) alternative in largemouth bass (Micropterus salmoides) (48.0 ± 0.03 g). Four isonitrogenous and isoenergetic diets were formulated including one commercial control (C, 42% FM) and three experimental diets with gradient FK of 3% (FK3, 29%FM), 6% (FK6, 26%FM) and 9% (FK9, 23%FM), respectively. FK-fed groups showed significantly higher SR than that of C group. The WGR and SGR of fish fed FK3 and FK6 were significantly higher than those of FK9, but not statistical different from the C group. FK-fed groups showed higher apparent digestibility coefficients of dry matter and nutrients. Further, FK-fed groups increased the ratio of SOD/MDA in the plasma and liver, and the upregulation of intestinal Keap1 and downregulation of HIF1α was found in FK3. Furthermore, FK-fed groups showed higher microbial richness and diversity. Pearson correlation analysis found that antioxidant relevant biomarkers were negatively correlated with the relative abundance of certain potential beneficial bacteria. In conclusion, supplemented up to 3–6% FK replacing FM in a low FM diet of largemouth bass could increase growth, survival rate, antioxidant capacity, and improve gut microbiota.

Subchronic feeding, allergenicity, and genotoxicity safety evaluations of single strain bacterial protein

Microbial proteins are potentially important alternatives to animal protein. A safety assessment was conducted on a Clostridium protein which can serve as a high-quality protein source in human food. A battery of toxicity studies was conducted comprising a 14-day dose-range finding dietary study in rats, 90-day dietary study in rats and in vitro genotoxicity studies. The allergenic potential was investigated by bioinformatics analysis. In the 90-day feeding study, rats were fed diets containing 0, 5.0, 7.5, and 10% Clostridium protein. The Clostridium protein-containing diets were well-tolerated and no adverse effects on the health or growth were observed. Significant reductions in neutrophil counts were observed in all female rats compared to controls, which were slightly outside of reference ranges. These effects were not deemed to be adverse due to the absence of comparable findings in male rats and high physiological variability of measured values within groups. A No-Observed-Adverse-Effect-Level (NOAEL) of at least 10% Clostridium protein, the highest dose tested and corresponding to 5,558 and 6,671 mg/kg body weight/day for male and female rats, respectively, was established. No evidence of genotoxicity was observed and the allergenic potential was low. These results support the use of Clostridium protein as a food ingredient.

Effects of Lysine Cell Mass Supplementation as a Substitute for L-Lysine·HCl on Growth Performance, Diarrhea Incidence, and Blood Profiles in Weaning Pigs

This study was conducted to evaluate the effects of lysine cell mass (LCM) as an alternative lysine source in diets for weaning pigs on growth performance, diarrhea incidence, and blood profiles. In experiment 1, a total of 200 weaning pigs, with an average body weight (BW) of 6.89 ± 1.04 kg, were allotted into one of five treatments with four replicates of 10 pigs per pen in a randomized complete block design (RCBD). The dietary treatments were composed of LCM supplementation (0, 0.25, 0.5, 0.75, or 1.0%) with partial replacement of L-lysine·HCl (0 to 0.8% for phase 1 diets and 0 to 0.07% for phase 2 diets). The BW and feed intake were recorded at the end of each phase (d 0 to 14 for phase 1, d 14 to 35 for phase 2), and diarrhea incidence was checked daily throughout the experimental period. Blood samples were taken from the jugular vein of pigs at 2 weeks and 5 weeks to determine the blood profiles of weaning pigs. In experiment 2, a total of 144 weaning pigs with an average BW of 6.44 ± 1.19 kg were allotted into one of six treatments with six replicates of four pigs per pen in RCBD. The dietary treatments were composed of LCM supplementation (0 to 3.5% for phase 1 diets and 0 to 2.2% for phase 2 diets) with replacement of L-lysine·HCl from 0 to 100%. In experiment 1, partial replacement of L-lysine·HCl with 0 to 1% LCM did not affect growth performance and diarrhea incidence of pigs. An increase in the LCM supplementation from 0 to 1% with partial replacement of L-lysine·HCl had no influence on the blood urea nitrogen concentrations, whereas it resulted in a linear decrease (p < 0.05) in the serum IgG concentrations for 5 weeks. In experiment 2, increasing the dietary level of LCM with replacement of L-lysine·HCl quadratically decreased (p < 0.05) ADG and G-F ratio for phase 2 and G-F ratio for the overall period such that 100% replacement of L-lysine·HCl with LCM decreased ADG and G-F ratio of weaning pigs. An increase in the LCM supplementation with replacement of L-lysine·HCl tended to decrease linearly (p < 0.10) the diarrhea incidence of weaning pigs for the overall period and linearly decrease (p < 0.05) the serum IgG concentrations for 2 weeks. In conclusion, partial replacement of L-lysine·HCl with LCM from 0 to 1% had no negative impacts on the growth performance, but 100% replacement of L-lysine·HCl with LCM decreased the growth performance of weaning pigs. Therefore, LCM could be included in the diets for weaning pigs up to 2.8% and 1.76% for phase 1 and phase 2, respectively, as a substitute for L-lysine·HCl without detrimental effects on the performance of weaning pigs.

Methanotrophic Bacterial Biomass as Potential Mineral Feed Ingredients for Animals

Microorganisms play an important role in animal nutrition, as they can be used as a source of food or feed. The aim of the study was to determine the nutritional elements and fatty acids contained in the biomass of methanotrophic bacteria. Four bacterial consortia composed of Methylocystis and Methylosinus originating from Sphagnum flexuosum (Sp1), S. magellanicum (Sp2), S. fallax II (Sp3), S. magellanicum IV (Sp4), and one composed of Methylocaldum, Methylosinus, and Methylocystis that originated from coalbed rock (Sk108) were studied. Nutritional elements were determined using the flame atomic absorption spectroscopy technique after a biomass mineralization stage, whereas the fatty acid content was analyzed with the GC technique. Additionally, the growth of biomass and dynamics of methane consumption were monitored. It was found that the methanotrophic biomass contained high concentrations of K, Mg, and Fe, i.e., approx. 9.6–19.1, 2.2–7.6, and 2.4–6.6 g kg⁻¹, respectively. Consequently, the biomass can be viewed as an appropriate feed and/or feed additive for supplementation with macroelements and certain microelements. Moreover, all consortia demonstrated higher content of unsaturated acids than saturated ones. Thus, methanotrophic bacteria seem to be a good solution, in natural supplementation of animal diets.

Effects of single cell protein replacing fish meal in diet on growth performance, nutrient digestibility and intestinal morphology in weaned pigs

Three experiments were conducted to evaluate the ME value, standardized ileal digestibility (SID) of amino acids (AA) of fish meal, and the effects of single cell protein (Prosin and Protide) replacing fish meal in diet on growth performance, nutrient digestibility and intestinal morphology in weaned piglets. In Exp. 1, twenty-four barrows with initial BW of 30.8±2.6 kg were allotted to one of four dietary treatments. Diet 1 contained corn as the only energy source. The other three diets replaced 20% of the corn in diet 1 with one of the three protein feeds (fish meal, Prosin and Protide), and the DE and ME contents were determined by difference. In Exp. 2, eight barrows (initial BW of 25.6±3.2 kg) were fitted with ileal T-cannulas and allotted to a replicated 4×4 Latin square design. Three cornstarch-based diets were formulated using each of the protein feeds as the sole source of AA. A nitrogen-free diet was also formulated to measure endogenous losses of AA. In Exp. 3, one hundred and eighty piglets (initial BW of 7.95±1.59 kg) weaned at 28±2 d were blocked by weight and assigned to one of five treatments for a 28-d growth performance study, each treatment was fed to six pens with six pigs (three barrows and three gilts) per pen. The five treatments consisted of the control group (CON), which was a corn-soybean meal diet containing 5% fish meal, and the other four treatments, which replaced a set amount of fish meal with either Prosin (2.5% or 5%) or Protide (2.5% or 5%). The diets were formulated to provide same nutrient levels. The results showed that on a DM basis, both of the DE and ME contents were lower in Prosin and Protide than that of fish meal (p<0.05). The SID of CP and all essential AA were greater in fish meal than in Prosin and Protide (p<0.05). The pigs fed CON diet had greater weight gain and lower feed conversion rate (FCR) than pigs fed 5% Prosin and 5% Protide diets (p<0.05). The digestibility of CP was greater in pigs fed CON, 2.5% Prosin and 2.5% Protide diets than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). Villus height in jejunum and ileum, and villus height to crypt depth ratio in the jejunum were higher (p<0.05) in pigs fed CON, 2.5% Prosin and 2.5% Protide diets compared with the 5% Prosin and 5% Protide diets. Pigs fed CON diet had greater villus height to crypt depth ratio in the ileum than the pigs fed 5% Prosin and 5% Protide diets (p<0.05). In conclusion, although Prosin and Protide contained lower ME content and SID of AA than fish meal, Prosin and Protide replacing 50% of fish meal in diet with identical nutrient levels could obtain similar performance, nutrient digestibility and intestinal morphology in weaned pigs.

Evaluation of methane-utilising bacteria products as feed ingredients for monogastric animals

Bacterial proteins represent a potential future nutrient source for monogastric animal production because they can be grown rapidly on substrates with minimum dependence on soil, water, and climate conditions. This review summarises the current knowledge on methane-utilising bacteria as feed ingredients for animals. We present results from earlier work and recent findings concerning bacterial protein, including the production process, chemical composition, effects on nutrient digestibility, metabolism, and growth performance in several monogastric species, including pigs, broiler chickens, mink (Mustela vison), fox (Alopex lagopus), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Atlantic halibut (Hippoglossus hippoglossus). It is concluded that bacterial meal (BM) derived from natural gas fermentation, utilising a bacteria culture containing mainly the methanotroph Methylococcus capsulatus (Bath), is a promising source of protein based on criteria such as amino acid composition, digestibility, and animal performance and health. Future research challenges include modified downstream processing to produce value-added products, and improved understanding of factors contributing to nutrient availability and animal performance.

Blood parameters in growing pigs fed increasing levels of bacterial protein meal

The experiment investigated the effects of increasing dietary levels of bacterial protein meal (BPM) on various blood parameters reflecting protein and fat metabolism, liver function, and purine base metabolism in growing pigs. Sixteen barrows were allocated to four different experimental diets. The control diet was based on soybean meal. In the other three diets soybean meal was replaced with increasing levels of BPM, approximately 17%, 35%, and 50% of the nitrogen being derived from BPM. Blood samples from the jugular vein were taken when the body weights of the pigs were approximately 10 kg, 21 kg, 45 kg, and 77 kg. The blood parameters reflecting fat metabolism and liver function were not affected by diet. Both the plasma albumin and uric acid concentrations tended to decrease (P = 0.07 and 0.01, respectively) with increasing dietary BPM content, whereas the plasma glucose concentration tended to increase (P = 0.07) with increasing dietary BPM content. It was concluded that up to 50% of the nitrogen could be derived from BPM without affecting metabolic function, as reflected in the measured blood parameters.

Effect of bacterial protein meal on protein and energy metabolism in growing chickens

This experiment investigates the effect of increasing the dietary content of bacterial protein meal (BPM) on the protein and energy metabolism, and carcass chemical composition of growing chickens. Seventy-two Ross male chickens were allocated to four diets, each in three replicates with 0% (D0), 2% (D2), 4% (D4), and 6% BPM (D6), BPM providing up to 20% of total dietary N. Five balance experiments were conducted when the chickens were 3-7, 10-14, 17-21, 23-27, and 30-34 days old. During the same periods, 22-h respiration experiments (indirect calorimetry) were performed with groups of 6 chickens (period 1), 5 chickens (period 2), and one chicken (periods 3-5). After each balance period, one chicken in each cage was killed and the carcass weight was recorded. Chemical analyses were performed on the carcasses from periods 1, 3, and 5. Weight gain, feed intake, and feed conversion rate were found to be similar for all diets. Chickens on D0 retained 1.59 g N x kg(-0.75) x d(-1), significantly more than chickens on D2, D4, and D6, which retained 1.44 g, 1.52 g, and 1.50 g N x kg(-0.75) x d(-1), respectively. This was probably caused by the higher nitrogen content of DO. Neither the HE (p = 0.92) nor the retention of energy (p = 0.88) were affected by diet. Carcass composition was similar between diets, in line with the values for protein and energy retention found in the balance and respiration experiments. It was concluded that the overall protein and energy metabolism as well as carcass composition were not influenced by a dietary content of up to 6% BPM corresponding to 20% of dietary N.