Endothermy in Birds and Mammals: How the Relationships between Body Weight and Metabolic Rate, Body Temperature, Sleep and Activity Duration Developed in the History of Formation of Endothermic Vertebrates | Chapter 3 | Innovations in Biological Science Vol. 4

 

Here we present a meta-analysis of literature sources and original data on basal metabolic rates (BMR) in birds and mammals based on 1817 measurements (817 data points from mammals and 1000 from birds). We used these data to estimate scaling coefficients and intercept for all endothermic animals pooled and for birds and mammals separately to study the difference between these classes, and also for the main groups of lower taxonomic status. We considered BMR variation and the duration of activity in three mammalian subclasses: monotremes, marsupials and eutherians, and in three groups of birds: palaeognaths, neognaths non-passerine and passerines, depending on the evolutionary age of these groups. In all groups BMR varies with body size with the different scaling coefficient which is statistically indistinguishable from ¾ in mammals and 2/3 un birds, but with significantly different intercepts. The data for all the considered groups were combined and the common exponent for six allometric equations between the BMR and body weight was established b = 0.7248. Reduced to the common slope, the relative metabolic rate forms the following series: Neognathae - Passeriformes - 1.00, Neognathae - Non-Passeriformes - 0.75, Palaeognathae - 0.53, Eutheria - 0.57, Marsupialia - 0.44, and Monotremata - 0.26. The main finding is that the metabolic rate in the six main groups of mammals and birds consistently increases as the geological time of the group’s divergence approaches the present.

 

Activity duration varies between the main groups of endotherms. Overall sleep duration is a parameter inversely related to the overall activity. A high level of activity is related to high BMR. Placentals and paleognaths have similar BMR, i.e. terrestrial lifestyle without flight is based on nearly equal BMR.

 

We calculated sleep duration in the main groups of endotherms on the basis of literature data. BMR in a taxon correlates with its evolutionary age: the later a clade diverged, the higher is its metabolic rate and the longer is activity period. BMR of eutherians and flightless paleognaths is similar, and these groups evolved at practically the same time. We suggest that each group formed its taxon-specific BMR depending on the ability to maintain thermal homeostasis under the environmental conditions that prevailed during its emergence. Monotremes were the first to branch off from the basal mammals and have the lowest BMR among the endotherms we consider. This level is minimally sufficient for maintaining homeostatic body temperature under a very limited range of environmental conditions. The next level is typical of marsupials and allows them to maintain thermal homeostasis under a broader range of conditions and have a more protracted period of activity. Finally, the metabolic rate typical of placentals and paleognaths formed in the mid-Cretaceous and allowed these groups to occupy a broader range of terrestrial niches. Immediately when the development of blood circulation and respiratory systems made it possible to reach the BMR that allowed maintaining a body temperature of 37 oC, the explosive radiation of mammals and birds started. In the mid and late Cretaceous birds and mammals started to occupy the leading positions in the ecosystems. And at last, some 50 mya passerines that have the highest BMR (nearly 50% higher than eutherians and paleognath birds) adapted to the forest habitats and gained body temperature of ca. 40oC, which is at the upper physiological limit. The duration of activity and body temperature increased in parallel to the BMR. Ecological expansion of birds and mammals resulted in their worldwide geographic distribution. A relatively similar energetic analogue of passerines in mammals are humans, who have BMR ca. 35% higher than predicted by the scaling equation for mammals, have amazing reproductive potential, large brains and longevity much exceeding the live duration which is typical for their body-mass specific mean. Sleep duration in humans is 30% shorter than the mammals-specific mean, and it is one of the evolutionary youngest species. At the moment the global population of humans exceeds 8 billion people.

 

Author(s) Details

Valery M. Gavrilov

Department of Vertebrate Zoology and Zvenigorod Biological Station, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.

 

Please see the book here:- https://doi.org/10.9734/bpi/ibs/v4/3716G

Seasonal Cycle of Leydig Cells in Birds | Chapter 3 | Achievements and Challenges of Medicine and Medical Science Vol. 4

In seasonally breeding birds, an increase in testicular recrudescence mainly involves gamete production, Sertoli cell development and an increased number of Leydig cell production. After successful breeding, a rapid postnuptial testicular regression occurs. An investigation was done to elucidate seasonal histomorphological changes of Leydig cells in Japanese Jungle crows (Corvus macrorhynchos). Histologic data of Leydig cells regarding their locations in the interstitium, appearance and disappearance of lipoidal materials in their cytoplasm, and fibroblasts like precursor cells were studied. The photomicrographs were processed with Adobe Photoshop CS5 for expected size and DPI and saved in JPG format. Finally, the photomicrographs were numbered and placed in the manuscript. In the non-breeding season, in the interstitium, clusters of Leydig cells were found in abundant numbers. They looked foamy, white and easily visible. Their nuclei were found small and are located eccentrically. During recrudescence, the Leydig cell became less foamy and less white. In peak breeding season, the Leydig cells showed bigger in size and the nuclei became prominent. Cytoplasmic lipoidal material was lowest and cytoplasm was found dense pink. At the end of the breeding period, a heavy accumulation of lipid materials occurred in the Leydig cell. The clusters of Leydig cells were visible and looked white and foamy again. During this transition, disintegration of Leydig cells occurred after pycnotic nuclei of Leydig cells were found. During involution, a new generation of fibroblast-like cells appeared in the interstitium. Within the fibroblast-like cells, some of them became lipoidal by accumulating lipid materials. Thus a new generation of Leydig cells appeared in the interstitium. These lipoidal cells are thought to be a new generation of Leydig cells for the next breeding season. This study suggests that in seasonally breeding birds, new generation of Leydig cell is derived from fibroblastlike cells of the interstitium. The study concluded that the beginning of the regeneration phase marks the end of the secretory cycle of the Leydig cells although their ultimate fate seems to be in doubt. During this period a new generation of interstitial cells is derived from fibroblast-like cells. Further studies are needed on how quantitative information on histo-architectures of Leydig cells at the ultrastructural level correlates with serum LH (luteinizing hormone) and testosterone levels during breeding and nonbreeding season in wild birds.

 

Author (s) Details

 

Muhammad Nazrul Islam
Department of Animal Science, Faculty of Agriculture, Utsunomiya University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan and Department of Anatomy and Histology, Faculty of Veterinary and Animal Science, Sylhet Agricultural University, Sylhet-3100, Bangladesh.

 

Masato Aoyama
Department of Animal Science, Faculty of Agriculture, Utsunomiya University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan.

 

Shoei Sugita
Department of Animal Science, Faculty of Agriculture, Utsunomiya University, 350 Minemachi, Utsunomiya, Tochigi 321-8505, Japan.

 

Please see the book here:- https://doi.org/10.9734/bpi/acmms/v4/2672  

Endothermy in Birds and Mammals: How the Relationships between Body Weight and Metabolic Rate, Body Temperature, Sleep and Activity Duration Developed in the History of Formation of Endothermic Vertebrates | Chapter 3 | Innovations in Biological Science Vol. 4

Here we present a meta-analysis of literature sources and original data on basal metabolic rates (BMR) in birds and mammals based on 1817 measurements (817 data points from mammals and 1000 from birds). We used these data to estimate scaling coefficients and intercept for all endothermic animals pooled and for birds and mammals separately to study the difference between these classes, and also for the main groups of lower taxonomic status. We considered BMR variation and the duration of activity in three mammalian subclasses: monotremes, marsupials and eutherians, and in three groups of birds: palaeognaths, neognaths non-passerine and passerines, depending on the evolutionary age of these groups. In all groups BMR varies with body size with the different scaling coefficient which is statistically indistinguishable from ¾ in mammals and 2/3 un birds, but with significantly different intercepts. The data for all the considered groups were combined and the common exponent for six allometric equations between the BMR and body weight was established b = 0.7248. Reduced to the common slope, the relative metabolic rate forms the following series: Neognathae - Passeriformes - 1.00, Neognathae - Non-Passeriformes - 0.75, Palaeognathae - 0.53, Eutheria - 0.57, Marsupialia - 0.44, and Monotremata - 0.26. The main finding is that the metabolic rate in the six main groups of mammals and birds consistently increases as the geological time of the group’s divergence approaches the present.

Activity duration varies between the main groups of endotherms. Overall sleep duration is a parameter inversely related to the overall activity. A high level of activity is related to high BMR. Placentals and paleognaths have similar BMR, i.e. terrestrial lifestyle without flight is based on nearly equal BMR.

We calculated sleep duration in the main groups of endotherms on the basis of literature data. BMR in a taxon correlates with its evolutionary age: the later a clade diverged, the higher is its metabolic rate and the longer is activity period. BMR of eutherians and flightless paleognaths is similar, and these groups evolved at practically the same time. We suggest that each group formed its taxon-specific BMR depending on the ability to maintain thermal homeostasis under the environmental conditions that prevailed during its emergence. Monotremes were the first to branch off from the basal mammals and have the lowest BMR among the endotherms we consider. This level is minimally sufficient for maintaining homeostatic body temperature under a very limited range of environmental conditions. The next level is typical of marsupials and allows them to maintain thermal homeostasis under a broader range of conditions and have a more protracted period of activity. Finally, the metabolic rate typical of placentals and paleognaths formed in the mid-Cretaceous and allowed these groups to occupy a broader range of terrestrial niches. Immediately when the development of blood circulation and respiratory systems made it possible to reach the BMR that allowed maintaining a body temperature of 37ºС, the explosive radiation of mammals and birds started. In the mid and late Cretaceous birds and mammals started to occupy the leading positions in the ecosystems. And at last, some 50 mya passerines that have the highest BMR (nearly 50% higher than eutherians and paleognath birds) adapted to the forest habitats and gained body temperature of ca. 40ºС, which is at the upper physiological limit. The duration of activity and body temperature increased in parallel to the BMR. Ecological expansion of birds and mammals resulted in their worldwide geographic distribution. A relatively similar energetic analogue of passerines in mammals are humans, who have BMR ca. 35% higher than predicted by the scaling equation for mammals, have amazing reproductive potential, large brains and longevity much exceeding the live duration which is typical for their body-mass specific mean. Sleep duration in humans is 30% shorter than the mammals-specific mean, and it is one of the evolutionary youngest species. At the moment the global population of humans exceeds 8 billion people.

Author(s) Details:

Valery M. Gavrilov,
Department of Vertebrate Zoology and Zvenigorod Biological Station, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.

Please see the link here: https://stm.bookpi.org/IBS-V4/article/view/14392

A Short Review on Chicken Heterophil | Chapter 8 | Research Aspects in Agriculture and Veterinary Sciences Vol. 1

 Heterophils are the most important leukocytes in phagocytosis in birds. Polymorphonuclear leukocytes (heterophils) are a type of polymorphonuclear leukocyte. They're a part of the body's natural defence mechanism. When hens come into contact with diseases, they have a primary response. Heterophils are mammalian counterparts to neutrophils; like neutrophils, they respond swiftly to infections and become activated quickly, thanks to chemotaxis. Bacteria, their proteins, and their structures are detected by Toll Like Receptors (TLRs), which are specialised receptors found in immune cells. They contain antibacterial chemicals that are released when germs come into contact with them. Their roles are determined by genetics. They are phagocytic, and their antimicrobial activity may be measured in a variety of methods.

Author (s) Details

N. Anand Laxmi
ICAR- Directorate of Poultry Research, Rajendranagar, Hyderabad, India.

View Book :- https://stm.bookpi.org/RAAVS-V1/article/view/2422