Salmonella Gallinarum field isolates and its relationship to vaccine strain SG9R.

1. The aim of the present study was to determine if the 9R-strain of the Salmonella Gallinarum live vaccine was responsible for having fowl typhoid outbreaks in chicken flocks from both chicken and turkey breeders as well as to verify the antimicrobial resistance of the isolates from the outbreaks. 2. The triplex polymerase chain reaction, standard antimicrobial test, beta-lactamase genes identification and Ion Torrent PMG whole-genome sequence were used in the field isolates and in the vaccine strain of S. Gallinarum. 3. The 60 tested isolates were not from vaccine origin and manifested high resistance to drugs from macrolide and quinolone groups. Whole-genome sequencing (WGS) and single nucleotide polymorphism analysis on selected isolates for core genes from Salmonella enterica confirmed the wild origin of these isolates and showed two possible sources of S. Gallinarum in the studied outbreaks. 4. S. Gallinarum isolated from fowl typhoid outbreaks in the studied period were not caused by the use of the SG9R live vaccine. The source of strains sequenced was diverse.

Effects of aflatoxins on performance and exocrine pancreas of broiler chickens.

The aim of this research was to evaluate, on a weekly basis, the effects of aflatoxins on the activity of digestive enzymes (alpha-amylase, lipase, and trypsin) in the pancreas as well as on the performance and histology of pancreas in broiler chickens over the course of 42 days. One thousand and eighty 1-day-old male Cobb broilers were divided into four treatments with 18 replicates and 15 birds per replicate (i.e., 270 broilers per treatment). Treatments were established according to the amount of aflatoxins added to the diet, as follows: T1 = 0 mg of aflatoxins per kilogram of feed (mg/kg); T2 = 0.7 mg/kg; T3 = 1.7 mg/kg; and T4 = 2.8 mg/kg. Pancreas sample collection was performed from one bird out of each replicate at 7, 14, 21, 28, 35, and 42 days of experiment, which yielded a total of 18 samples per treatment on each collection. Each sample was homogenized in distilled water, frozen in liquid nitrogen, lyophilized, and stored at -20 C until analysis. Performance parameters (body weight, feed consumption, and feed conversion rate) were measured at 21, 35, and 42 days of experiment. At the end of the experiment (42 days), six birds from each treatment were randomly chosen for histologic evaluation of the pancreas. The presence of aflatoxins in the diet induced a negative effect on all performance parameters. The pancreatic activity of lipase and alpha-amylase were significantly increased in treatments T3 and T4, while the specific activity of trypsin was only affected during treatment T4. In addition, several histologic changes were observed in the pancreas of birds receiving aflatoxin-contaminated feed. Aflatoxins present in the feed determined an increase in the activity of pancreatic enzymes in broilers, affecting the digestibility of the diet, thereby leading to losses in performance and productivity.

Individual and combined effects of Salmonella typhimurium lipopolysaccharide and fumonisin B1 in broiler chickens.

The aim of this research was to evaluate the individual and combined effects of Salmonella typhimurium lipopolysaccharide (sLPS) and fumonisin B(1) (FB) on performance, relative weight of liver, biological parameters, and histological evaluation of several tissues from four hundred thirty-two 1-d-old male broiler chickens divided into 9 treatments according to the dose of FB (0, 100, or 200 mg/kg, from d 1 to d 28) and sLPS (0, 250, or 500 µg/application per bird, every other day, from d 15 to 27) administered. At the end of the experiment (28 d), significant effects caused by sLPS, FB, and the interaction of sLPS × FB were observed on several parameters. Histopathological evaluations showed significant lesions in liver and kidney caused by sLPS, FB, and their association. According to these results, both sLPS and FB (isolated or in association) cause significant effects on performance and biological parameters of broilers at 28 d of age.

Performance of turkey poults fed different doses of aflatoxins in the diet.

This work was conduced to determine the performance parameters of initial-phase turkey poults fed 7 different doses of aflatoxins in the diet. Three hundred thirty-six 1-d-old male turkey poults were used in this research. Turkeys were divided into 7 treatments according to aflatoxin doses (T1 = control; T2 = 20 ppb aflatoxins; T3 = 50 ppb; T4 = 100 ppb; T5 = 200 ppb; T6 = 500 ppb; T7 = 1,000 ppb). Birds were killed in 2 periods: half of them after 21 d of experiment and the remaining birds after 42 d of experiment. In both periods, the evaluated parameters were as follows: feed consumption, BW, relative weights of organs (liver, gizzard, heart, and bursa of Fabricius) and meat (breast and thighs), and clinical biochemistry parameters (total plasmatic proteins, albumin, uric acid, cholesterol, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase). At 21 d of experiment, both feed consumption and BW were significantly affected by the aflatoxins present in the diet. Nevertheless, gizzard relative weight, total plasmatic proteins, and cholesterol levels were also affected. At the 42-d evaluation, besides feed consumption and BW, gizzard and liver relative weights and cholesterol levels were also affected by the presence of aflatoxins in the diet. Turkey poults are very sensitive to aflatoxin poisoning, because they are at least 3 to 6 times more sensitive to these contaminants than broilers.