Background: Cerebral amyloid angiopathy (CAA) is a disorder characterized by amyloid deposition in the wall of cerebral blood vessels. The deposits of amyloid occur frequently in the blood vessels of the frontal, parietal and occipital cortex. Objective: To examine the characteristics of CAA classified according to the Vonsattel scale in elderly dogs histologically and immunohistochemically as well as the semi-quantitative evaluation of the amyloid deposits in the different segments of the brain. Animals and methods: The brains of 36 dogs of different breeds and sexes, which had been routinely necropsied, were used and divided into two groups: dogs from 1 to 5 and 10 to 18 years old. The tissue sections were stained by hematoxylin–eosin, Congo red and immunohistochemically. Results: Amyloid was accumulated in the wall of cerebral blood vessels in 70% of dogs over the age of 10 years predominantly in the frontal cortex. CAA was demonstrated in elderly dogs as follows: in the frontal cortex (n = 19 or 63%), the parietal cortex (n = 12 or 40%), the hippocampus (40%) and the cerebellum (n = 5 or 17%). The deposits of amyloid in the wall of blood vessels detected by Congo red staining were also Aβ1-14 and Aβ1-42 immunohistochemically positive. Most commonly, the amyloid deposits affected a moderate number of blood vessels. The accumulation of amyloid was immunohistochemically revealed in the blood vessel walls as well as in the senile plaques and neurons. Conclusion: The amount of amyloid in the arterial walls increased with age in dogs, whereas the amyloid accumulated in plaques was Congo red negative.

D-galactose (d-gal) plays numerous roles in the organism as an energy-providing nutrient and also an important constituent of the complex glycoconjugates. However, excessive amounts of d-gal activate alternative metabolic pathways that can lead to the development of a pro-oxidative environment. This feature is used in numerous aging studies which implied intraperitoneal (i.p.) or subcutaneous (s.c.) administration of d-gal for a prolonged time. The present study aims to investigate the systemic effects of orally administered d-gal (200 mg/kg and 500 mg/kg, dissolved in tap water, for 6 weeks) by analyzing oxidative stress parameters in the liver, kidney, and heart. For comparison with natural aging, the effects were studied in rats aged 12, 18, 24, and 30 months. In addition, histopathologic analyzes and serum biochemical measurements were performed to investigate the potential structural and functional organ damage induced by d-gal administration. Our findings show that chronic oral administration of d-gal induces oxidative stress in rat organs and mimics some aspects of natural aging similar to those of 30-month-old rats. Consistent with its primary role in galactose metabolism, the liver exhibited the most pronounced oxidative damage. However, despite the increased oxidative stress, only minor histopathological changes were observed, while organ function remained largely unaffected. Oral intake of d-gal was found to have milder effects compared to i.p. or s.c. injections, suggesting that this model may induce some features of natural aging but without overt organ dysfunction.

This study examined pathomorphological changes and meat quality alterations associated with Wooden Breast Myopathy (WB) in total of 192 broiler chickens divided into Ross 308 (n=96) and Cobb 500 (n=96) heavy hybrids at ages 42, 60, and 70 days. WB occurrence remained consistently high (>73%) across periods, peaking on day 70 (83% for Ross, 90% for Cobb). Cobb broilers had better production results and carcass traits parameters after day 42 and day 60 of the experiment (p≤0.05). Genotype did not affect WB occurrence or severity, while slaughter age influenced severe cases WB occurrence, increasing from 11.67% on day 42 to 36.67% on day 70 (p=0.003). The presence of WB was associated with higher ultimate pH, lightness (L*), redness (a*), and yellowness (b*) of the muscle (p<0.0001), except on day 70. Physicochemical and color parameters were also influenced by slaughter age (p<0.0001). On day 42, drip loss (p<0.0001), cooking loss (p≤0.05) and shear force (p<0.0001) were affected by genotype. On days 60 and 70, the differences in water retention capacity were observed only between normal and severely affected breasts (p<0.0001). For each slaughter age severely affected WB had higher shear force compared to normal breasts (p<0.0001). Additionally, with the increasing slaughter age of broilers, drip loss, cooking loss, and shear force of the breast meat were increased (p<0.0001). The results obtained regarding the occurrence and severity of WB and its consequent meat quality alterations suggest that extended fattening is not recommended for poultry production.

The ageing process is accompanied by numerous changes in the brain of dogs, such as accumulation of amyloid, fibrosis of blood vessel walls and meninges, accumulation of lipofuscin, and the presence of polyglucosan bodies (PGBs), satellitosis and neuronophagia. In this study, the presence of lipofuscin and PGBs in various parts of the brain in dogs of different sexes and ages was examined. For this purpose, brain samples were stained using haematoxylin eosin, modified Ziehl Neelsen and Periodic acid Schiff (PAS) methods. Lipofuscin was visualised by Ziehl Neelsen and PAS methods of specific staining on the same brain tissue segments. Lipofuscin had accumulated in 93% of old (more than 10 years old) dog brains, mostly in neurons of the medulla oblongata. The percentage of age-related lipofuscin pigment in other examined brain tissue segments was lower than in the medulla oblongata. There was a small difference in the percentage of lipofuscin-positive individuals between the two staining methods. The presence of PGBs was established by the PAS method for the vast majority (about 93%) of the old dogs (more than 10 years old), while PGBs were not detected in the group of young dogs (up to 5 years old). However, PGBs occurred in all examined segments of the dog?s brain tissues (for each of the tissue types, from 90% to 93% of dogs were positive for PGBs). The results obtained the oldest dogs (15 years old) harboured PGBs both extracellularly and intracellularly, while in other dogs, only extracellular PGBs were seen. Lipofuscin was accumulated mostly in large neurons of olivary nuclei of the medulla oblongata. PGBs were confirmed in all examined segments of the brain tissue of dogs more than 10 years old. This is one of the numerous indications that old dogs could be a very good animal model for studying the normal ageing process or neurodegenerative diseases.

Scrapie is an infectious neurodegenerative disease affecting the central nervous system of sheep and goats that belongs to transmissible spongiform encephalopathies. The disease is caused by the accumulation of proteinase-resistant isoform of the prion protein. The sheep predisposition to scrapie is associated with polymorphisms of the PrP gene. Genetic susceptibility to scrapie is mainly related to codons 136, 154, and 171. ARR sheep are strongly scrapie resistant and VRQ genotype is the most susceptible. Many countries have scrapie eradication programs based on using rams with resistant genotype. The eradication program has not yet been implemented in the Republic of Serbia. To examine the genetic makeup of sheep in Serbia related to scrapie, we optimized TaqMan probes of real-time polymerase chain reaction (qPCR) technique for three codons. Blood samples from 100 sheep were analyzed by qPCR and the majority of the examined sheep were AA homozygous for the 136 codon. For codon 154 the most frequent genotype was RR and for codon 171 the most frequent genotype was QQ.

An experiment was conducted in a commercial broiler farm to evaluate birds’ growth performance, intestinal morphology (IM), and total blood carotenoid levels when adding different inclusion rates of microbial muramidase (MUR) to broilers’ feed formula. A total of 336-day-old broilers from Ross 308 were assigned to three groups and were fed from day 1 to day 42. Treatment 1 (T1), the control treatment, was a basal corn soybean meal diet that followed Aviagen nutrient specifications; Treatment 2 (T2) was the control treatment + 350 g MUR per ton of feed; Treatment 3 (T3) was the control treatment + 450 g MUR per ton of feed. Body weight gain (BWG), feed intake (FI), the feed conversion ratio (FCR), carotenoid levels (CLs), and IM from samples of the duodenum, jejunum, and ileum were evaluated on day 42. MUR significantly outperformed the control diet in terms of body weight (BW), resulting in BWs of 2513 g (p = 0.005) and 2463 g with T3 and T2, respectively, versus 2377 g with T1. Daily weight gain (DWG) was 58.77 g and 57.58 g in T3 and T2 (p = 0.0004), respectively, versus 55.54 g in T1. The Daily Feed Intake (DFI) on day 42 was higher in T3 compared to T1 (98.90 g p < 0.0001 versus 97.72 g). The morphology results show higher effects in the duodenum with T3 versus T2 and T1. In addition, the results were significantly higher in the jejunum when using T2 and T3 compared to T1. Goblet cells were not influenced by MUR use in the diets. The broilers’ blood carotenoid levels were significantly higher in T3 (1.75 mg/L p = 0.0026) compared to T1 (1.02 mg/L). These results shed light on broilers’ performance, intestinal health, and nutrient availability when using MUR at different inclusion rates in broiler feed for broilers raised under near-commercial conditions.