Publications by authors named "Jeferson Lourenco"

10 Publications

  • Page 1 of 1

Probiotics and potential applications for alternative poultry production systems.

Poult Sci 2021 Mar 26;100(7):101156. Epub 2021 Mar 26.

Faculty of Bioengineering of Animal Resources, Banat University of Animal Sciences and Veterinary Medicine - King Michael I of Romania, Timisoara, Romania. Electronic address:

Concerns over animal welfare continue to be a critical component of law and policies associated with commercial food animal production. Social and market pressures are the driving forces behind the legislation and result in the change of poultry production management systems. As a result, the movement toward cage-free and aviary-based egg production systems has become standard practices. Cage-based systems being replaced by alternative methods that offer a suitable housing environment to meet or exceed poultry welfare needs and require different management, including the ban of antibiotics in poultry diets. For broiler production, pasture- raised and free-range management systems have become more popular. However, challenges remain from exposure to disease-causing organisms and foodborne pathogens in these environments. Consequently, probiotics can be supplemented in poultry diets as commercial feed additives. The present review discusses the impacts of these probiotics on the performance of alternative poultry production systems for improving food safety and poultry health by mitigating pathogenic organisms and improving egg and meat quality and production.
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http://dx.doi.org/10.1016/j.psj.2021.101156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8181177PMC
March 2021

An overview of health challenges in alternative poultry production systems.

Poult Sci 2021 Mar 27;100(7):101173. Epub 2021 Mar 27.

Department of Animal and Dairy Science, University of Georgia, Athens, GA. Electronic address:

Due to consumer demand and changing welfare standards on health, ecology, equity, and safety concepts, poultry production has changed markedly over the past 20 y. One of the greatest changes to poultry production standards is now offering poultry limited access to the outdoors in alternative and organic poultry production operations. Although operations allowing access to the outdoors are still only a small portion of commercial poultry production, it may impact the gastrointestinal (GIT) health of the bird in different ways than birds raised under conventional management systems. The present review describes current research results in alternative systems by identifying how different poultry production operations (diet, environmental disruptive factors, diseases) impact the ecology and health of the GIT. Various research efforts will be discussed that illustrate the nutritional value of free-range forages and how forages could be beneficial to animal health and production of both meat and eggs. The review also highlights the need for potential interventions to limit diseases without using antibiotics. These alternatives could enhance both economics and sustainability in organic and free-range poultry production.
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http://dx.doi.org/10.1016/j.psj.2021.101173DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8170424PMC
March 2021

The Effects of Feeding Antibiotic on the Intestinal Microbiota of Weanling Pigs.

Front Vet Sci 2021 12;8:601394. Epub 2021 Mar 12.

Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States.

This study investigated the use of carbadox in the diet of nursery pigs. Ten pens of weanling piglets were assigned to 2 treatments: one containing carbadox and another without it. From days 21 to 35 of age, the first group of piglets was fed carbadox at 55 mg/kg of diet; followed by 27.5 mg/kg from days 36 to 49; and 0 mg/kg from days 50 to 63. The second group of pigs was fed a control diet without carbadox from days 21 to 63 of age. On days 35, 49, and 63, fecal samples were collected directly from the rectum of 2 piglets in each pen, and the samples were subjected to microbial DNA sequencing and metagenomic functional analysis using the 16S rRNA gene. Feed conversion from days 21 to 63 was improved ( = 0.04) in the group of piglets fed carbadox. Faith's phylogenetic diversity was similar ( = 0.89) for both groups of piglets on day 35, but it was diminished ( = 0.01) in the carbadox-fed group on day 49; however, following the complete removal of carbadox from their diets, this microbial diversity index was once again found to be similar ( = 0.27) in both groups on day 63. Likewise, abundances of , and were all similar between the two groups ( ≥ 0.40) on day 35, but were smaller in the carbadox group ( ≤ 0.05) on day 49; however, on day 63, abundances of all these genera were once again similar ( ≥ 0.29). Metabolic pathways involved in cellular growth, death, and genetic information processing (translation) were found to be similarly expressed in the microbiota of piglets from both groups on day 35 ( ≥ 0.52), but decreased in the carbadox group on day 49 ( ≤ 0.05), and were similar again in both groups on day 63 ( ≥ 0.51). These results revealed that feeding carbadox to piglets during the first 4 weeks after weaning significantly affected their fecal microbiotas; however, 2 weeks after the removal of carbadox, those changes tended to disappear, indicating that the shifts were carbadox-dependent.
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http://dx.doi.org/10.3389/fvets.2021.601394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996051PMC
March 2021

Dynamic Changes in the Gut Microbiome at the Acute Stage of Ischemic Stroke in a Pig Model.

Front Neurosci 2020 3;14:587986. Epub 2020 Dec 3.

Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA, United States.

Stroke is a major cause of death and long-term disability affecting seven million adults in the United States each year. Recently, it has been demonstrated that neurological diseases, associated pathology, and susceptibility changes correlated with changes in the gut microbiota. However, changes in the microbial community in stroke has not been well characterized. The acute stage of stroke is a critical period for assessing injury severity, therapeutic intervention, and clinical prognosis. We investigated the changes in the gut microbiota composition and diversity using a middle cerebral artery (MCA) occlusion ischemic stroke pig model. Ischemic stroke was induced by cauterization of the MCA in pigs. Blood samples were collected prestroke and 4 h, 12 h, 1 day, and 5 days poststroke to evaluate circulating proinflammatory cytokines. Fecal samples were collected prestroke and 1, 3, and 5 days poststroke to assess gut microbiome changes. Results showed elevated systemic inflammation with increased plasma levels of tumor necrosis factor alpha at 4 h and interleukin-6 at 12 h poststroke, relative to prestroke. Microbial diversity and evenness were reduced at 1 day poststroke compared to prestroke. Microbial diversity at 3 days poststroke was negatively correlated with lesion volume. Moreover, beta-diversity analysis revealed trending overall differences over time, with the most significant changes in microbial patterns observed between prestroke and 3 days poststroke. Abundance of the Proteobacteria was significantly increased, while Firmicutes decreased at 3 days poststroke, compared to prestroke populations. Abundance of the lactic acid bacteria was reduced at 3 days poststroke. By day 5, the microbial pattern returned to similar values as prestroke, suggesting the plasticity of gut microbiome in an acute period of stroke in a pig model. These findings provide a basis for characterizing gut microbial changes during the acute stage of stroke, which can be used to assess stroke pathology and the potential development of therapeutic targets.
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http://dx.doi.org/10.3389/fnins.2020.587986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7744295PMC
December 2020

The relationship between the rumen microbiome and carcass merit in Angus steers.

J Anim Sci 2020 Sep;98(9)

Department of Animal and Dairy Science, University of Georgia, Athens, GA.

The objective of this study was to explore the relationships between ruminal microbial populations from Angus steers that were divergent in carcass traits related to adipose accumulation. Twenty-four feedlot-finished Angus steers (age: 538 ± 21 d; body weight following lairage: 593.9 ± 43.7 kg) were slaughtered, and ruminal contents and carcass data were collected. Ruminal microbial deoxyribonucleic acid (DNA) extraction and 16S ribosomal ribonucleic acid (rRNA) gene sequencing were performed to determine microbial relative abundances, to estimate microbial diversity, and to predict microbial metabolic pathways. A variety of correlation analyses and one-way ANOVA were performed to investigate the relationships between the rumen microbiome and carcass traits. Marbling score (P = 0.001) and longissimus lipid content (P = 0.009) were positively correlated to Chao1 Richness Index, suggesting that increased intramuscular fat was associated with increased numbers of ruminal microbial species. The phyla Tenericutes and TM7 were negatively correlated (P ≤ 0.05) to marbling score and longissimus lipid content, indicating that lower abundances of these phyla may be associated with improvements in intramuscular fat content. Greater abundance of the bacterial family S24-7 was positively correlated (P = 0.002) to marbling score. Analysis by marbling classification revealed further linkages to microbial richness (P ≤ 0.063), diversity (P = 0.044), and S24-7 (P < 0.001) populations. Computational prediction of the microbial metabolic pathways revealed no differences (P ≥ 0.05) in metabolic pathway expression in rumen microbes between steers in the high- and low-marbling classes. Several phyla, families, and genera were positively correlated (P ≤ 0.05) to both rib fat thickness and yield grade. Collectively, our results suggest that microbial composition is associated to differing performance in carcass adipose traits. Overall, most of the bacterial taxa correlated to the intramuscular and subcutaneous fat depots did not overlap, suggesting the microbial population end products likely impacted adipose accumulation largely via separate adipogenic pathways of the host animal.
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http://dx.doi.org/10.1093/jas/skaa287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7526868PMC
September 2020

The impact of feed efficiency selection on the ruminal, cecal, and fecal microbiomes of Angus steers from a commercial feedlot.

J Anim Sci 2020 Jul;98(7)

Department of Animal and Dairy Science, University of Georgia, Athens, GA.

Feed is the greatest cost of animal production, so reducing it is critical to increase producer profits. In ruminants, the microbial population within the gastrointestinal tract (GIT) is critical to nutrient digestion and absorption in both the rumen and the hindgut. The objective of this study was to determine the bacterial taxonomic profile of the rumen, cecum, and feces of feedlot steers at slaughter in order to link feed efficiency and the GIT bacterial populations from these three locations. Twenty commercial Angus steers were selected and divided into two groups according to their residual feed intake (RFI) classification determined during the feedlot-finishing period: high-RFI (n = 10) and low-RFI (n = 10). After the ruminal, cecal, and fecal samples were collected at slaughter, DNA extraction and 16S rRNA gene sequencing were performed on them to determine their bacterial composition. One-way ANOVA was performed on the animal performance data, alpha diversities, and bacterial abundances using RFI classification as the fixed effect. Overall, the ruminal bacterial population was the most different in terms of taxonomic profile compared with the cecal and fecal populations as revealed by beta diversity analysis (P < 0.001). Moreover, bacterial richness (Chao1) was greatest (P = 0.01) in the rumen of the high-RFI group compared with the low-RFI group. In contrast, bacterial richness and diversity in the intestinal environment showed that Chao1 was greater (P = 0.01) in the cecum, and the Shannon diversity index was greater in both the cecum and feces of low-RFI compared with high-RFI steers (P = 0.01 and P < 0.001, respectively). Ruminococcaceae was more abundant in the low-RFI group in the cecum and feces (P = 0.01); fecal Bifidobacteriaceae was more abundant in high-RFI steers (P = 0.03). No correlations (P ≥ 0.13) between any ruminal bacterial family and RFI were detected; however, Ruminococcaceae, Mogibacteriaceae, Christensenellaceae, and BS11 were negatively correlated with RFI (P < 0.05) in the cecum and feces. Succinivibrionaceae in the cecum was positively correlated with RFI (P = 0.05), and fecal Bifidobacteriaceae was positively correlated with RFI (P = 0.03). Results collectively indicate that in addition to the ruminal bacteria, the lower gut bacterial population has a significant impact on feed efficiency and nutrient utilization in feedlot steers; therefore, the intestinal bacteria should also be considered when examining the basis of ruminant feed efficiency.
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http://dx.doi.org/10.1093/jas/skaa230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7392532PMC
July 2020

Comparison of the ruminal and fecal microbiotas in beef calves supplemented or not with concentrate.

PLoS One 2020 13;15(4):e0231533. Epub 2020 Apr 13.

Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States of America.

Most of the research efforts involving the bovine gastrointestinal microbiota have focused on cattle's forestomach, particularly the rumen, so information concerning the bovine fecal microbiota is more scarce, especially in young beef cattle. The present study was performed to evaluate the ruminal and fecal microbiotas of beef calves as they reached the end of their nursing phase. A total of 18 Angus cow/calf pairs were selected and assigned to one of two treatment groups for the last 92 days of the calves' nursing period, as follows: 1) calves were supplemented with concentrate in a creep feeding system; or 2) control group with no supplementation of calves. After 92 days, ruminal and fecal samples were individually obtained from calves in both groups, and their microbiotas were evaluated using 16S rRNA gene sequencing. Ruminal samples were predominated by Prevotella (18 to 23% of the total bacterial abundance), regardless if calves received supplementation or not; however, in the feces, Prevotella was only the seventh most abundant genus (0.6 to 2.1% of total bacterial abundance). Both the rumen (P = 0.01) and the feces (P = 0.05) of calves that received supplementation had greater abundance of Firmicutes. In addition, calves that were supplemented had lower abundance of Fibrobacteres (P = 0.03) in their rumens. Regardless if the calves were supplemented or not, Faith's Phylogenetic Diversity index (P ≤ 0.007) and total concentration of short chain fatty acids (P < 0.001) were both greater in the rumen than in the feces of calves. In summary, the ruminal and fecal microbiotas of weanling beef calves were considerably distinct. Additionally, supplementation with creep feed caused some significant changes in the composition of the gastrointestinal microbiota of the calves, especially in the rumen, where supplementation caused an increase in Firmicutes and a decrease in abundance of Fibrobacteres.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0231533PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7153887PMC
July 2020

Effect of Supplemental Protease on Growth Performance and Excreta Microbiome of Broiler Chicks.

Microorganisms 2020 Mar 27;8(4). Epub 2020 Mar 27.

Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602, USA.

One-day-old chicks were assigned one of four dietary treatments in a 2 × 2 factorial design in which the main effects were diet (adequate vs. low protein) and the addition of protease (0 vs. 200 g/1000 kg of feed). Chick performance (days 0-14) was recorded and their excreta were analyzed for short chain fatty acids, ammonia, and composition of the microbiota using 16S rRNA gene sequencing. Birds fed the low protein diet had lower body weight gain and poorer overall feed conversion ratio (FCR) ( 0.04); however, these parameters were not affected by the inclusion of protease ( 0.27). Protease inclusion did not affect any particular bacterial genus in the excreta, but it increased the total number of observed OTUs ( = 0.04) and Faith's phylogenetic diversity ( = 0.05). Abundance of and were lower in the excreta of chicks fed the low protein diet ( = 0.01). Abundance of was associated with poorer FCR, while was associated with improved FCR ( 0.009). Although diet had a stronger impact than protease on chick performance, both diet and protease yielded some changes in the intestinal microbiotas of the birds.
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http://dx.doi.org/10.3390/microorganisms8040475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7232218PMC
March 2020

Analysis of the Rumen Microbiota of Beef Calves Supplemented During the Suckling Phase.

Front Microbiol 2019 28;10:1131. Epub 2019 May 28.

Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States.

A study was conducted to examine the effects of supplementing beef calves during their suckling phase (popularly known as creep feeding) with supplements that contained or did not contain the enzyme xylanase. Forty-two cow-calf pairs were divided into three groups and assigned to one of three treatments for a period of 105 days, as follows: (1) No supplemental feed for calves (control; CON); (2) Corn and soybean meal-based supplement feed for calves (positive control; PCON); and (3) Same feed regimen as PCON with xylanase added to the supplement (enzyme; ENZ). After 105 days, out of the 42 calves participating in the study, 25 male calves were randomly selected (8 from CON, 9 from PCON, and 8 from ENZ) and samples of their forestomach were collected by esophageal tubing. Immediately after this procedure, all calves were weaned, commingled, and placed in a common post-weaning diet for 4 weeks. At the end of this period, ruminal fluid was once again collected from the same 25 calves. All samples were subjected to DNA extraction and 16S rRNA gene sequencing. At weaning, most of the alpha diversity indexes were greater in CON; however, no differences ( ≥ 0.23) in alpha diversity were observed in samples collected 4 weeks after weaning. Regardless of treatment, 2 phyla - and - comprised approximately 80% of the total bacterial abundance of samples collected on both days. At the genus level, an effect of diet ( = 0.02) was observed for in the samples collected at weaning; however, no differences were detected in the samples collected 4 weeks after weaning. Calf average daily gain (ADG) during the 105-day creep feeding trial tended ( = 0.09) to be greater in the groups that received supplementation, with the greatest numerical value observed in ENZ. Moreover, there was a positive correlation (ρ = 0.43; = 0.03) between ADG and abundance of , indicating the importance of this bacterial group for ruminants. In summary, most of the significant differences found in this study were detected at weaning, and the majority of them disappeared 4 weeks after the calves were weaned and commingled.
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http://dx.doi.org/10.3389/fmicb.2019.01131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547912PMC
May 2019

Comparison of follicular development, timing of ovulation and serum progesterone, estradiol and luteinizing hormone concentrations in dairy heifers treated with 4- or 5-day CoSynch + CIDR protocols.

Vet Med Sci 2019 08 22;5(3):379-389. Epub 2019 Apr 22.

Department of Large Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.

The use of 4-day CoSynch + Controlled internal drug release (CIDR) + timed artificial insemination (TAI) in dairy heifers has resulted in adequate pregnancy rates compared with the 5-day CoSynch + CIDR + TAI protocol. The objective of this study was to compare follicular growth, timing of ovulation and serum progesterone (P ), estradiol (E ) and luteinizing hormone (LH) concentrations in dairy heifers treated with modified 4- or 5-day CoSynch + CIDR protocols (CIDR for 4 or 5 days, PGF α at CIDR removal and GnRH + TAI 72 h later). Twelve cycling Holstein heifers were randomly assigned to either the 4- or 5-day Co-Synch+CIDR (n = 6/treatment) to receive an intravaginal insert CIDR containing 1.38 g of P for 4 or 5 days, respectively. At CIDR removal, 25 mg of PGF α was injected IM; 72 h after CIDR removal, heifers received 100 μg of GnRH IM and timed artificial insemination (TAI). Follicular growth and timing of ovulation were assessed using transrectal ultrasonography. Blood samples were collected at the time of CIDR insertion and at frequent time points after CIDR removal for determination of P (at TAI), E (every 12 h) and LH (every 6 h during the first and second day and every 2 h on the third day). Heifers in the 4-day group had smaller follicles from CIDR insert removal to ovulation compared with heifers in the 5-day treatment. Five of six heifers (83.3%) in the 4-day treatment ovulated at 90-96 h post CIDR insert removal, whereas most heifers in the 5-day treatment (4/6; 66.6%) ovulated at 84-90 h post CIDR insert withdrawal. Heifers in the 5-day treatment reached greater peak LH concentration between 48 and 72 h after CIDR insert removal and lesser E concentration at TAI than heifers in the 4-day treatment. In conclusion, heifers in the 4-day treatment had smaller follicular diameter at 0, 30, 36, 42 and 48 h after CIDR insert removal, longer interval from CIDR insert removal to ovulation, greater E concentrations at TAI, and lesser peak LH concentration than heifers in the 5-day treatment. These results represent a baseline for further studies to determine if prolonging the interval to TAI by 6 h in the 4-day CoSynch+CIDR would improve pregnancy risk.
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http://dx.doi.org/10.1002/vms3.171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6682797PMC
August 2019