The effect of humic substances on gut microbiota and immune response of broilers

G, Hargis BM, Téllez-Isaías G. Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B1-Contaminated Diet

A recent study published data on the growth performance, relative weights of the organs of the gastrointestinal tract, liver histology, serum biochemistry, and hematological parameters for turkey poults fed an experimental diet contaminated with aflatoxin B1 (AFB1) and humic acids (HA) extracted from vermicompost. The negative effects of AFB1 (250 ng AFB1/g of feed) were significantly reduced by HA supplementation (0.25% w/w), suggesting that HA might be utilized to ameliorate the negative impact of AFB1 from contaminated diets. The present study shows the results of the remaining variables, as an extension of a previously published work which aimed to evaluate the impact of HA on the intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity of turkey poults fed an AFB1-contaminated diet. For this objective, five equal groups of 1-day-old female Nicholas-700 turkey poults were randomly assigned to the following treatments: negative control (basal diet), positive control (basal diet + 250 ng AFB1/g), HA (basal diet + 0.25% HA), HA + AFB1 (basal diet + 0.25% HA + 250 ng AFB1/g), and Zeolite (basal diet + 0.25% zeolite + 250 ng AFB1/g). In the experiment, seven replicates of ten poults each were used per treatment (n = 70). In general, HA supplementation with or without the presence of AFB1 showed a significant increase (p < 0.05) in the number of beneficial butyric acid producers, ileum villi height, and ileum total area, and a significant reduction in serum levels of fluorescein isothiocyanate-dextran (FITC-d), a marker of intestinal integrity. In contrast, poults fed with AFB1 showed a significant increase in Proteobacteria and lower numbers of beneficial bacteria, clearly suggesting gut dysbacteriosis. Moreover, poults supplemented with AFB1 displayed the lowest morphometric parameters and the highest intestinal permeability. Furthermore, poults in the negative and positive control treatments had the lowest cutaneous basophil hypersensitivity response. These findings suggest that HA supplementation enhanced intestinal integrity (shape and permeability), cellular immune response, and healthier gut microbiota composition, even in the presence of dietary exposure to AFB1. These results complement those of the previously published study, suggesting that HA may be a viable dietary intervention to improve gut health and immunity in turkey poults during aflatoxicosis.

The Effect of the Supplementation of Humic Substances and Fermented Products in the Feed on the Content of Salinomycin Residues in Poultry Tissues

The presence of antimicrobial residues in products of animal origin is a constant problem for consumer health. The aim of this study was to observe the effect of the addition of humic substances (H), fermented products (F) and a mixture of both (FH) to feed supplemented with the coccidiostat salinomycin, compared with a control group (C), on the content of salinomycin residues in the edible tissues of broiler chickens using two microbial inhibition screening methods, Explorer 2.0 test and the Screening Test for Antibiotic Residues (STAR), and a confirmatory competitive enzyme immunoassay analysis (Salinomycin ELISA Kit). The results of the microbial inhibition tests showed a gradual decline in the positive results in the tissue samples from the last day of salinomycin administration (30th day) tothe last day of fattening (37th day, day of slaughter) in group C and no positive results in the tissue samples from experimental groups H, F and FH slaughtered on the last day of fattening. Using the Salinomycin ELISA Kit, salinomycin was detected in the chicken muscle tissues of all the control and experimental groups. However, no sample from any group contained salinomycin at a concentration exceeding the maximum residue limits set by European law. The high level of significance (p < 0.001) confirmed the positive influence of the administration of humic substances and fermented products on the content of salinomycin residues in chicken tissues.

Effect of probiotics and humate substances on blood parameters, intestinal development and immune organs of growing quail

This study aimed to evaluate impacts of dietary probiotics (Bacillus subtilis PB6) and humate substances (HS) supplementation on histomorphometry of small intestine and immune organs, blood parameters of growing quail. A total of 216 unsexed quails (seven days old) were randomly distributed to six groups. The 1st group did not receive any supplements (control), 2nd group received B. subtilis (CloSTAT: 0.5 g/kg diet), 3rd and 4th groups received HS (4 and 8 g/kg diet, respectively), 5th and 6th groups received CloSTAT + 4g HS and CloSTAT + 8g HS, respectively. Results showed that the inclusion of B. subtilis alone in quail diets significantly improved histomorphometry indices of intestine and immune organs compared to the control. Dietary supplementation of HS alone led to deteriorating histomorphometry indices of intestinal segments and immune organs compared to the control. CloSTAT, HS or both improved lipid profile and antioxidant parameters. Serum mineral levels did not differ significantly among groups except for Ca levels. In conclusion, dietary probiotics supplementation enhanced histomorphometry of intestine and immune organs and improved serum Ca, lipid profile and antioxidant indices. Moreover, the addition of HS (4 or 8 g/kg diet) improved lipid profile and antioxidant indices, but led to undesirable results in intestinal development and immune organs.

Humic acids alleviate aflatoxin B1-induced hepatic injury by reprogramming gut microbiota and absorbing toxin

Aflatoxin B1 (AFB1) is a hepatotoxic fungal metabolite that is widely present in food and can cause liver cancer. As a potential detoxifier, naturally occurring humic acids (HAs) may be able to reduce inflammation and restructure the gut microbiota composition; however, little is known about the mechanism of HAs detoxification as applied to liver cells. In this study, HAs treatment alleviated AFB1-induced liver cell swelling and the infiltration of inflammatory cells. HAs treatment also reinstated various enzyme levels in the liver disturbed by AFB1 and substantially alleviated AFB1-caused oxidative stress and inflammatory responses by enhancing immune functions in mice. Moreover, HAs increased the length of the small intestinal and villus height to restore intestinal permeability, which is impaired by AFB1. In addition, HAs reconstructed the gut microbiota, increasing the relative abundance of Desulfovibrio, Odoribacter, and Alistipes. In vitro and in vivo assays demonstrated that HAs could efficiently remove AFB1 by absorbing the toxin. Therefore, HAs treatment can ameliorate AFB1-induced hepatic injury by enhancing gut barrier function, regulating gut microbiota, and adsorbing toxin.

Humic Substances as a Feed Supplement and the Benefits of Produced Chicken Meat

Humic substances with a high proportion of humic acids (more than 40%) have been classified by the European Commission as feed materials that can be used in animal nutrition since 2013. A protective effect on the intestinal mucosa, as well as anti-inflammatory, adsorptive and antimicrobial properties, were recorded. Nutrient absorption, nutritional status and the immune response in chickens supplemented with HSs were significantly improved. HSs have the ability to enhance protein digestion as well as the utilization of calcium and trace elements. They are known to improve feed digestibility as a result of maintaining an optimal pH in the gut, leading to lower levels of nitrogen excretion and less odor in the husbandry environment. HSs not only increase digestibility and result in greater utilization of the feed ration but also improve the overall quality of the meat produced. They increase the protein content and reduce the fat content in breast muscles. They also contribute to improving the sensory characteristics of the meat produced. Their antioxidant properties improve the oxidative stability of meat during storage. The influence of HSs on fatty acid composition may be one of the reasons that meat has a more beneficial effect on the health of consumers.

Amylolytic and Cellulolytic Activities, the Digestibility of Dry Matter of Broiler Chickens After Feed Intake of Humic Substances

This study aimed to investigate the effects of feed intake of humic substances (HS) on the cellulolytic and amylolytic activities, and the digestibility of dry matter (DM) in the chymus of the intestine and ileum of broiler chickens (Cobb 500). Four groups of birds (A, B, C, negative control; n = 120) were fed with mash diets (starter HYD1 230.20, grower HYD2 222.20, finisher HYD3 209.40 g crude protein (CP) per kg of DM) with the added HS from day 1 to 37 days as follows: A ‒ 0.7 % Humac nature; B ‒ 0.7 % Humac nature monogastric (HNM); C ‒ 0.5 % HNM (Humac Ltd., Slovakia). The cellulolytic activities were increased in the intestine in B/C by 2.50 (P < 0.01)/1.65 (P < 0.05) on day 3 and 1.02 (P < 0.001)/0.3 (P < 0.05) µmol.l−1.min−1.g−1 on day 24. There were observed higher values of digestibility coefficient of DM in the intestine (P < 0.05) in C by 15.14 % and 14.85 %, and in B by 20.73 % on days 17, 24 and 31, respectively. The enhancement of ileal digestibility of DM was observed in B by 7.38 % (P < 0.05) and CP in A and B by 3.7% and 6.1% (P < 0.05). The feed intake of HS favourably influenced the cellulolytic activities and increased the DM digestibility in the intestine and the ileum, as well as the CP digestibility in the ileum.

Ameliorative impacts of sodium humate on heat-stressed laying Japanese quail (Coturnix coturnix Japonica)

A total of 300 laying Japanese quails (230.10 ± 20 g body weight) divided into four groups (15 birds in 5 replicates/group) were used to examine the impacts of dietary sodium humate (SH) supplementation at levels of 0% (control diet), 0.2%, 0.4% and 0.6% on egg variables and physiological merits of laying quails for 10 weeks under heat stress conditions (15 June and 23 August 2021). Results showed 0.4% SH increased (p < 0.05) weight (12.27 vs. 11.91 g), production (79.84% vs. 69.20%), mass (597.13 vs. 510.48 g) and brokenness (2.8% vs. 5.4%) of eggs as compared to control. Egg shape, shell thickness, shell strength and cholesterol content as well as feed conversion ratio were higher (80.2, 295.8 µm, 1.468 kg/cm,² 11.08 mg/g and 2.69, p < 0.05) in 0.4% SH than in control group (75.2, 279.0 µm, 1.304 kg/cm,²  14.94 mg/g and 2.76). Feed intake, percentages of eggs' shells, yolk, albumen and serum biochemistry (total protein, albumin, AST and HDL) were not altered with the dietary SH. Birds fed on SH diets showed higher levels of globulin, calcium and phosphorus, as well as lower contents of albumin/globulin ratio, triglycerides, cholesterol, corticosterone compared with the control. Regression analysis of antioxidants expected higher total antioxidant capacity (TAC), superoxide dismutase, glutathione peroxidase at 0.35%, and glutathione at 0.40% SH, while the lowest concentration of malondialdehyde was computed at 0.45%. Similarly, immunoglobulins (IgG and IgM) maximum values were determined at 0.35% and 0.40% levels. Moreover, the concentration of tumour necrosis factor-alpha increased (p < 0.05) in all SH levels as compared to the control group. It is conceivable to conclude that the dietary implementation of SH at a level of 0.4% improved egg variables and well-being aspects of laying quail exposed to heat stress conditions.

Effect of the Addition of Humic Substances on Morphometric Analysis and Number of Goblet Cells in the Intestinal Mucosa of Broiler Chickens

The mechanisms of action of humic substances (HS) as growth promoters in poultry are unknown. In this study, the productive performance, histology, and number of goblet cells (GC) in the intestinal villi of broilers under steady-state digestive conditions and under abrupt changes in diet with the addition of HS was evaluated. Broilers housed individually were offered three treatments from 14−28 days: 1 = diet with white corn/soybean meal, without growth promoter antibiotics (nonGPA); 2 = with GPA (GPA); and 3 = with 0.3% HS. At day 28, two diets were suddenly introduced: (A) white corn/soybean meal plus dried distillers’ grains with solubles (DDGS); and (B) white/blue corn/soybean meal/DDGS, keeping the three original treatments. Diets A and B were also exchanged on day 37. FCR was lower with GPA and HS compared to nonGPA from 14−38 days (p < 0.05); at day 28, under steady-state digestive conditions, HS had a similar effect to GPA on the histology and GC number in the jejunum villi. The number of GC in the jejunum of HS-fed broilers on days 29 and 38, after diet changes, behaves similarly to that of AGP-fed broilers (p > 0.05). HS appears to strengthen the mucosal protection of the epithelium of the intestine.

Effects of humic acid and organic acids supplements on performance, meat quality, leukocyte count, and histopathological changes in spleen and liver of broiler chickens

The aim of the present study is to evaluate the effect of Humic Acid (HA), Organic Acids (OA), and their combination (HAOA) on the growth performance, meat quality, leukocyte count, and histopathological changes in the liver and spleen of broiler chickens. A total of 2100 one-day-old mix-sexed broiler chickens were randomly divided into 4 groups with 5 replicates per treatment using 105 birds per pen (pen is used as an experimental unit). Treatments were: 1) Control (basal diet without additives), 2) Basal diet +0.1% HA, 3) Basel diet +0.1% HA+ 0.02% OA, 4) Basel diet +0.02% OA. Growth performance was not significantly affected by all dietary treatments during the experiment period. Sensory evaluation of breast meat indicated a significant positive response for color and smell corresponding to treatment 2) Basal diet +0.1% HA and treatment 3) Basel diet +0.1% HA+ 0.02% OA (P < 0.05). Birds receiving HA and HAOA developed fewer hepatic lesions compared to the control group (P < 0.05) and showed normal spleen structure with the extension of the white pulp area. Supplementation of HAOA corresponds to a lower heterophil to lymphocyte (H/L) ratio. The combination of HA and OA improves sensory attributes of cooked breast meat, H/L ratio, and preserves the histological structure of the spleen and liver of broiler chickens. HAOA can be recommended as a combined feed additive to improve broiler chickens' health.

Maintaining Optimal Mammary Gland Health and Prevention of Mastitis

In dairy industry, quality of produced milk must be more important than quantity without a high somatic cells count (SCC) or pathogens causing mastitis of dairy cows and consumer diseases. Preserving the good health of dairy cows is a daily challenge for all involved in primary milk production. Despite the increasing level of technological support and veterinary measures, inflammation of the mammary gland–mastitis, is still one of the main health problems and reasons for economic losses faced by cow farmers. The mammary gland of high-yielding dairy cows requires making the right decisions and enforcing the proper measures aimed at minimizing external and internal factors that increase the risk of intramammary infection. Due to the polyfactorial nature of mastitis related to its reduction, the effectiveness of commonly used antimastitis methods tends to be limited and therefore it is necessary to find the areas of risk in udder health programs and monitoring systems. Only by implementing of complete udder health programs should be accompanied by research efforts to further development these complete udder health control. The present review analyses the current knowledge dealing with damping and prevention of mastitis include SCC control, proper nutrition, housing and management, milking and drying as practiced in dairy farming conditions. This information may help to improve the health of the mammary gland and the welfare of the dairy cows as well as the production of safe milk for consumers.

Effect of diets containing earthworm powder and vermihumus on egg production, hatchability, blood parameters and immunity of Japanese breeder quails

The present study is aimed to evaluate the effects of different levels of earthworm (EW) powder and vermihumus (VH) on the growth performance, humoral immunity response, plasma constituents and reproductive performance of Japanese breeder quails. A total of 336 birds were assigned to seven treatments in a completely randomized design from day 30 to 90 of age. The dietary treatments were carried out, one without any addition of EW and VH, the second had a standard rate of VH at 0.8%, while a range of EW additions was supplied from 0%, 0.5%, 1%, 1.5%, 2% and 2.5%. The effects of treatments on body weight and mortality were not significant (p > .05). The highest feed intake was observed in birds fed the diets supplemented with 1% and 1.5% EW (p < .05). The highest titre of antibodies against influenza virus and sheep red blood cells belonged to the EW and VH treatments (p < .05). The antibody titre against Newcastle disease virus vaccine was not affected by the treatments. In general, the birds receiving EW and VH had the highest egg weight, egg production and egg mass weight (p < .05). Nonetheless, various levels of EW powder negatively affected hatchability and increased mortality and leg disorders (p < .05). The results showed that the levels of dietary 1% and 1.5% of EW powder gave the best growth and reproductive performance to birds respectively.

Impact of humic acid as an organic additive on the milk parameters and occurrence of mastitis in dairy cows

Given growing concerns about the use of antibiotics in the treatment of animals, identifying organic alternatives as feed additives to improve animal health and the development of immune responses has become of interest in dairy farming. Humic acids (HA) seem to be a suitable alternative with a favorable impact on the health and production parameters of animals. This study aimed to determine the effects of an HA supplemented diet on milk parameters as well as the effects on somatic cell count (SCC) and the occurrence of mastitis in dairy cows during the peripartum period. Twenty dairy cows in the last stage of pregnancy were selected from a herd of 140 cows. The selected cows were randomly divided into two groups: control (C) and experimental (E). The two groups were fed the same feed mixture and group E was additionally supplemented with HA at a total dose of 100 g per cow per day during the last 50 days of pregnancy. The milk parameters (dry matter, lactose, fat, crude protein, casein and milk urea) and SCC of every cow, and the presence of mastitis, were checked on days 10 and 30 during the first month of lactation. The results of the study show that dietary supplementation with HA significantly reduced the milk urea (MU) content and SCC on the 10th day after calving but did not affect the other milk compositions. In addition to the decreased MU and SCC, the number of positive quarters detected by the California Mastitis Test was reduced by 20.0% and the occurrence of mastitis caused by coagulase-negative staphylococci (CNS). Based on the obtained results we can conclude that the addition of HA stabilizes the nutrient digestion, as was confirmed by a reduced MU content in the supplemented group. Their indirect beneficial effects improved the development of immune responses, resulting in decreased SCC and the occurrence of mastitis caused by CNS.