Corrigendum: Evaluation of the efficacy of humic acids to counteract the toxic effects of aflatoxin B1 in turkey poults.

[This corrects the article DOI: 10.3389/fvets.2023.1276754.].

Evaluation of the efficacy of humic acids to counteract the toxic effects of aflatoxin B1 in turkey poults.

This study aims to evaluate the efficacy of humic acid (HA) from worm compost as an adsorbent for aflatoxin B1 (AFB1) in turkey poults. The experiment involved the inclusion of 0.25% (w/w) HA in the diet of turkey poults consuming aflatoxin-contaminated feed (250 ng AFB1/g). A total of 350 1-day-old female Nicholas-700 turkey poults were randomly allocated to five equal groups: negative control (basal diet); positive control (basal diet + 250 ng AFB1/g; HA (basal diet + 0.25% HA); HA + AFB1 (basal diet + HA + 250 ng AFB1/g); and zeolite + AFB1 (basal diet + 0.25% zeolite + 250 ng AFB1/g). Each group had seven replicates of 10 poults (n = 70). The impact of HA addition was evaluated in terms of performance parameters, relative organ weights, liver histological lesions, and serum biochemical and hematological constituents. In general, the addition of HA improved body weight (BW), body weight gain (BWG), and feed conversion rate (FCR). Furthermore, HA effectively mitigated the toxic effects caused by AFB1 in the majority of the analyzed variables. The results indicated that HA effectively counteracted the AFB1-induced toxic effects in turkey poults. Based on these findings, it can be concluded that HA is capable of removing AFB1 from the contaminated diet.

Humic Acids Preparation, Characterization, and Their Potential Adsorption Capacity for Aflatoxin B1 in an In Vitro Poultry Digestive Model.

Vermicompost was used for humic acid (HA) preparation, and the adsorption of aflatoxin B1 (AFB1) was investigated. Two forms of HA were evaluated, natural HA and sodium-free HA (SFHA). As a reference, a non-commercial zeolitic material was employed. The adsorbents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDS), zeta potential (ζ-potential), scanning electron microscopy (SEM), and point of zero charge (pHpzc). The adsorbent capacity of the materials when added to an AFB1-contaminated diet (100 µg AFB1/kg) was evaluated using an in vitro model that simulates the digestive tract of chickens. Characterization results revealed the primary functional groups in HA and SFHA were carboxyl and phenol. Furthermore, adsorbents have a highly negative ζ-potential at the three simulated pH values. Therefore, it appears the main influencing factors for AFB1 adsorption are electrostatic interactions and hydrogen bonding. Moreover, the bioavailability of AFB1 in the intestinal section was dramatically decreased when sorbents were added to the diet (0.2%, w/w). The highest AFB1 adsorption percentages using HA and SFHA were 97.6% and 99.7%, respectively. The zeolitic material had a considerable adsorption (81.5%). From these results, it can be concluded that HA and SFHA from vermicompost could be used as potential adsorbents to remove AFB1 from contaminated feeds.

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 acids on the recovery of different bacterial strains in an in vitro chicken digestive model.

Humic acids (HA) have been evaluated as growth promoters in poultry, but their effects on the gut microbiota remains controversial using in vitro and in vivo models. The objective of this study was to determine the effect of HA extracted from a wormcompost on the recovery of bacteria: Salmonella Enteritidis (S. Enteritidis), Escherichia coli (E. coli), Clostridium perfringens (C. perfringens), Bacillus subtilis (B. subtilis) and Lactobacillus salivarius (L. salivarius) using an in vitro chicken digestive system. Independent in vitro trials were run for each bacteria using six treatments: 1) Negative control with no bacteria added (Control-), 2) Positive control added with bacteria (Control+), 3) 0.1% HA + bacteria, 4) 0.2% HA + bacteria, 5) 0.5% HA + bacteria and 6) 1% HA + bacteria. Data was subjected to analysis of variance and linear regression. In the crop, S. Enteritidis was lower, C. perfringes and B. subtilis were not affected by HA, while E. coli and L. salivarius were higher at 0.5 and 1% HA inclusion (P ≤ 0.0001). In the proventriculus, S. Enteritidis, E. coli and B. subtilis were higher at 0.5 and 1% HA inclusion (P ≤ 0.0001); C. perfringens and L. salivarius were not affected by HA. In intestine, significant increases of all bacteria strains were observed (P ≤ 0.0001). In conclusion, the results suggests that HA can be used as prebiotic, but their mechanisms of action to stimulate the growth of gut bacteria remains to be elucidated.

Addition of Different Levels of Humic Substances Extracted from Worm Compost in Broiler Feeds.

Different sources and inclusion levels of humic substances (HS) have been tested in broiler rations as an alternative to the addition of growth promoter antibiotics (GPA) with promising results. The current study was carried out to assess the influence of HS extracted from worm compost on broiler production parameters, carcass yield, tibia characteristics, lactic acid bacteria (LAB) counts, excretion of Eimeria oocysts, and antioxidant status of breast meat. A total of 1200 broilers were used, housed in groups of 30 per pen, and assigned to five treatments: 1 = basal diet with GPA (positive control), 2 = basal diet without GPA (negative control), 3-5 = basal diet with 0.15, 0.30, and 0.45% HS, respectively. The data was subjected to a variance analysis and orthogonal contrasts. The FI decreased linearly (p < 0.05) from 1-14, 29-42, and 1-42 days as the inclusion of HS in the feed increased. The FCR had quadratic responses (p < 0.01) from 29-42 and 1-42 days concerning the HS inclusion levels. Lactic acid bacteria was higher (p ˂ 0.05) in ten-day-old chicks with 0.45% HS in the diet. The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity antioxidant potential decreased linearly (p < 0.05) concerning increasing HS in the feed. The results indicate that HS can be used as growth promoters in broiler feeds.

Effect of the Addition of Humic Substances as Growth Promoter in Broiler Chickens Under Two Feeding Regimens.

Humic substances (HS) from different sources have been evaluated to replace or reduce the use of growth promoter antibiotics (GPA) in the feeds of broiler chickens. The objective was to evaluate the growth performance, tibia measurements, nutrient balance, meat quality, and microbiological status of broiler fed with an HS extract (EHS) under ad libitum (ADLIB) or feed restriction (REST). Individually caged broilers (n = 180, 14-35 day of age) were assigned to a factorial arrangement of three dietary treatments: (1) positive control with bacitracin methylene disalicylate (BMD) and salinomycin; (2) negative control without BMD nor salinomycin, and (3) same as negative control with 0.25% EHS, and two feeding regimens 1) ADLIB or REST for 24 h on d 1, 7, and 14. Results were subjected to ANOVA. Positive control and EHS-fed broilers showed higher carcass yield (p < 0.05) and lower oocyst excretion (p < 0.01) compared to negative control birds. Lactic acid bacteria (LAB) and Clostridium perfringens (C. perfringens) were higher in negative control and EHS-broilers compared to positive control (p < 0.01). In conclusion, higher carcass yield, lower C. perfringens and oocyst excretion were found in positive control and higher carcass yield, higher LAB and lower oocyst excretion were found in EHS-fed broilers. Broilers subjected to REST had reduced growth performance and meat quality. In conclusion, EHS could be used to increase the carcass yield and beneficial LAB in broilers.

Efecto del espacio disponible/tamaño de grupo sobre el balance de nutrimentos en cerdos en finalización / Effect of the available space/group size on the nutrient balance of finishing pigs

The nitrogen and energy utilization of finishing pigs allocated individually or in groups of two was evaluated. Thirty two castrated males were used with an initial weight of 68.6 ± 1.0 kg that were assigned in a randomized complete block design with a split-plot arrangement in three treatments: a pig allocated individually with free access to feed and 0.81 m² of floor space (D1AL); two pigs allocated in group with free access to feed and 0.405 m² of floor space/pig (D2AL); a pig allocated individually paired-fed to the average consumption of pigs in D2AL and floor space similar to D1AL (D1P). The experiment was divided in two periods of excreta collection: days 1-4 and 18-21, respectively. There were eight repetitions per treatment. The nutrient consumption in period 1 was higher in D1AL compared to D2AL and D1P (density x period, P < 0.01); in period 2, the nutrient consumption was higher in D1AL, intermediate in D1P and lower in D2AL. The nitrogen (P < 0.05) and energy (P < 0.10) retained in period 1 was similar among densities (density x period interaction); in period 2 it was higher in D1AL compared to D2AL. The pigs housed in groups of two with free access to feed had lower nutrient consumption and retention at the end of the trial, probably as a consequence of chronic stress due to the competition for the feed, complicated by the restriction of available floor space.

Se evaluó la utilización de nitrógeno y energía en cerdos en finalización, alojados individualmente y en grupos de dos. Se usaron 32 machos castrados con un peso inicial de 68.6 ± 1.0 kg que fueron asignados al azar, en un diseño de bloques completos con arreglo en parcelas divididas en tres tratamientos: un cerdo alojado individualmente con libre acceso al alimento y 0.81 m² de espacio de piso (D1AL); dos cerdos alojados en grupo con libre acceso al alimento y 0.405 m² de espacio de piso/cerdo (D2AL); un cerdo alojado individualmente con consumo pareado con base en el consumo de los cerdos en D2AL y espacio de piso similar a D1AL (D1P). El experimento se dividió en dos periodos de recolección de excretas: días 1-4 (periodo 1) y 18-21 (periodo 2). Se tuvieron ocho repeticiones por tratamiento. El consumo de nutrimentos en el periodo 1 fue mayor en D1AL con respecto a D2AL y D1P (densidad x periodo, P < 0.01); en el periodo 2, el consumo de nutrimentos fue mayor en D1AL, intermedio en D1P y menor en D2AL. La retención de nitrógeno (P < 0.05) y de energía (P < 0.10) en el periodo 1 fue similar entre densidades (interacción densidad x periodo); en el periodo 2 fue mayor en D1AL comparado con D2AL. Los cerdos alojados en grupos de dos con alimentación a libertad tuvieron menor consumo y retención de nutrimentos en la fase final de la prueba, probablemente como consecuencia del estrés crónico debido a la competencia por el alimento, complicado por la restricción de espacio disponible de piso.