Functions of innate and acquired immune system are reduced in domestic pigeons (Columba livia domestica) given a low protein diet

Comparative Effect of Ascaridia Galli Infection on the Two Laying Hen Lines on the Liver Function and Immune Response

Chicken production is quickly rising due to the low associated costs and the capability of poultry to convert nutrients into biological protein along with chicken meat accounting for 30% of all animal protein eaten by humans. Despite advances in poultry production, parasitic illnesses in laying hens remain a problem. Farm birds reared in semi-intensive and free-range systems are more prone to parasite infections due to the absorption of polluted water and food from scavenging behaviors and waste droppings. In this study, the effects of Ascaridia galli infection on the immune response and liver function of two laying hen lines are compared, and their infection resistance is determined. In total, 50 laying hens at eight weeks of age were used (25 Lohmann brown-classic and 25 Lohmann lsl-lite), and each line was divided into two groups: an infected group (n=15), which was orally infected with a single dose of 500 A. galli embryonated eggs, and a control group (n=10), which was given normal saline. After four and eight weeks, blood was collected from the wing vein to assess the serum's AST, ALT, total protein, and IgY levels. The results demonstrated that the infected Lohmann brown-classic and Lohmann lsl-lite chickens presented significantly increased (P≤0.05) AST, ALT, and IgY, compared to the respective control group. Moreover, Lohmann brown-classic hens presented a significantly increased (P≤0.05) IgY concentration four weeks after infection, compared to Lohmann lsl-lite hens. From our results, it can be concluded that genetic variation plays a crucial role in the immune response against A. galli, where the Lohmann brown-classic line was found to be more resistant, compared to the Lohmann lsl-lite line.

Chemical Composition of Pigeon Crop Milk and Factors Affecting Its Production: A Review

Pigeons are important commercial poultry in addition to being ornamental birds. In 2021, more than 111 million pairs of breeding pigeons were kept in stock and 1.6 billion squabs were slaughtered for meat in China. However, in many countries, pigeons are not domestic birds; thus, it is necessary to elucidate the factors involved in their growth and feeding strategy due to their economic importance. Pigeons are altricial birds, so feedstuffs cannot be digested by squabs, which instead are fed a mediator named pigeon crop milk. During lactation, breeding pigeons (both female and male) ingest diets and generate crop milk to feed squabs. Thus, research on squab growth is more complex than that on chicken and other poultry. To date, research on the measurement of crop milk composition and estimation of the factors affecting its production has not ceased, and these results are worth reviewing to guide production. Moreover, some studies have focused on the formation mechanism of crop milk, reporting that the synthesis of crop milk is controlled by prolactin and insulin-activated pathways. Furthermore, the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) pathway, target of rapamycin (TOR) pathway and AMP-activated protein kinase (AMPK) pathway were also reported to be involved in crop milk synthesis. Therefore, this review focuses on the chemical composition of pigeon crop milk and factors affecting its production during lactation. This work explores novel mechanisms and provides a theoretical reference for improving production in the pigeon industry, including for racing, ornamental purposes, and production of meat products.

ENDOPARASITES IN THE SYNANTHROPIC FERAL PIGEON (COLUMBA LIVIA DOMESTICA) IN SOUTHERN ECUADOR

Parasitic infections are frequent in cosmopolitan feral pigeons (Columba livia domestica) that live in cities, but little is known about the effects of parasites in urban feral pigeon populations. A survey was conducted to evaluate the occurrence of endoparasites and the risk factors of feral pigeons in the city of Loja in southern Ecuador between August and October 2019. A total of 166 fecal samples and 80 peripheral blood smears were collected and examined by the McMaster flotation method and Giemsa staining, respectively. The prevalence of gastrointestinal parasites was 79.51% (132/166). Parasites included: Ascaridia columbae in 13.64% (18/132), Capillaria sp. in 3.79% (5/132), Eimeria sp. in 25% (33/132), unidentified coccidia in 75% (99/132), and an unidentified nematode egg in 0.7% (1/132). The presence of intracellular gamonts of Haemoproteus sp. was found in 87.50% (70/80) of examined blood smears. The frequency and intensity of nematodes were different according to the site. Haemoproteus infection was more frequent in individuals with low body mass index. More research should be undertaken to understand parasitic infections and their effects on cosmopolitan synanthropic feral pigeons.

Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases? A systematic narrative review

Respiratory Viruses infections (RVI) such as rhinovirus, coronavirus, influenza virus, and adenovirus affect the respiratory and the immune systems. The role of nutrition in the respiratory and immune systems has been studied in some studies, and its importance is undeniable. In addition, one of the key findings in this disease is high inflammation that affects almost all patients. This systematic narrative review aims to answer the question, "Can an anti-inflammatory diet be effective in preventing or treating viral respiratory diseases?" A systematic review search was used for the articles extraction. All studies published in English from 1999 to 2020 investigating dietary inflammatory conditions and RVI were included. Food items with anti-inflammatory properties were selected based on the definition of the dietary inflammatory index (DII). We used Google Scholar, Pub Med, Scopus, Web of Science, Springer, Science Direct, Directory of Open Access Journals, Elsevier, Taylor and Francis, ProQuest, EBSCO, MEDLINE, and SciELO databases for extracting articles. Keywords were restricted by DII. Based on DII, food items/nutrients are involved in inflammation, some of which have anti-inflammatory and some inflammatory properties. Some foods/nutrients, in addition to their anti-inflammatory properties, have antioxidant, antiviral, and immune-enhancing properties. Considering the immune system's involvement, increased inflammation, and involvement of the pulmonary system in RVI and the remarkable role of the anti-inflammatory foods for counteracting them, it is recommended to use a predominantly anti-inflammatory diet along with prevention/control and treatment protocols. An anti-inflammatory diet (based on DII) includes turmeric, ginger, garlic, onions, saffron, dietary vitamin C, vitamin D, zinc, and omega-3 are recommended to reduce infection symptoms and duration.

A fruit diet rather than invertebrate diet maintains a robust innate immunity in an omnivorous tropical songbird

Diet alteration may lead to nutrient limitations even in the absence of food limitation, and this may affect physiological functions, including immunity. Nutrient limitations may also affect the maintenance of body mass and key life‐history events that may affect immune function. Yet, variation in immune function is largely attributed to energetic trade‐offs rather than specific nutrient constraints.

To test the effect of diet on life‐history traits, we tested how diet composition affects innate immune function, body mass and moult separately and in combination with each other, and then used path analyses to generate hypotheses about the mechanistic connections between immunity and body mass under different diet compositions.

We performed a balanced parallel and crossover design experiment with omnivorous common bulbuls Pycnonotus barbatus in out‐door aviaries in Nigeria. We fed 40 wild‐caught bulbuls ad libitum on fruits or invertebrates for 24 weeks, switching half of each group between treatments after 12 weeks. We assessed innate immune indices (haptoglobin, nitric oxide and ovotransferrin concentrations, and haemagglutination and haemolysis titres), body mass and primary moult, fortnightly. We simplified immune indices into three principal components (PCs), but we explored mechanistic connections between diet, body mass and each immune index separately.

Fruit‐fed bulbuls had higher body mass, earlier moult and showed higher values for two of the three immune PCs compared to invertebrate‐fed bulbuls. These effects were reversed when we switched bulbuls between treatments after 12 weeks. Exploring the correlations between immune function, body mass and moult, showed that an increase in immune function was associated with a decrease in body mass and delayed moult in invertebrate‐fed bulbuls, while fruit‐fed bulbuls maintained body mass despite variation in immune function. Path analyses indicated that diet composition was most likely to affect body mass and immune indices directly and independently from each other. Only haptoglobin concentration was indirectly linked to diet composition via body mass.

We demonstrated a causal effect of diet composition on innate immune function, body mass and moult: bulbuls were in a better condition when fed on fruits than invertebrates, confirming that innate immunity is nutrient specific. Our results are unique because they show a reversible effect of diet composition on wild adult birds whose immune systems are presumably fully developed and adapted to wild conditions—demonstrating a short‐term consequence of diet alteration on life‐history traits.