Effects of feed supplementation on mineral composition, mechanical properties and structure in femurs of Iberian red deer hinds (Cervus elaphus hispanicus)

Concentration of Macroelements and Trace Elements in Farmed Fallow Deer Antlers Depending on Age

The mineral content of the antlers reflects the nutritional status and specific stage of bone growth in cervid males. Therefore, this research aimed to analyze the concentration of Ca, P, Mg, K, Na, Li, V, Cr, Mn, Co, Cu, Zn, Se and Mo in three characteristic antler positions selected based on the observation of fights between males. These were compared between farmed fallow deer (Dama dama) of different ages. The mineral compositions of tissues were analyzed using inductively coupled plasma mass spectrometry. The highest mean concentrations of macroelements (except K) were recorded in the youngest animals aged 2 or 3 years in the proximal position of the antlers. With age and distance from the skull, Ca, P, Mg and Na contents decreased, while K increased. Higher mean concentrations of most trace elements (Cr, Mn, Co, Cu, Zn) were recorded in 3-year-old animals in antler distal positions. With an increase in the age, body mass and antler mass of fallow deer, the concentration of Ca, P, Mg, K, Mn, Cu and Zn decreased (−0.414 ≤ R ≤ −0.737, p < 0.05) in the studied tissue, whereas Li increased (0.470 ≤ R ≤ 0.681, p < 0.05). The obtained results confirm that the antlers’ chemical composition changes with age, also changing the Ca:P ratio.

The Mineral Composition of Bone Marrow, Plasma, Bones and the First Antlers of Farmed Fallow Deer

An adequate supply of essential nutrients is particularly important during the skeletal growth and development of young deer, especially in males, who build new antlers each year. The aim of the research was to analyze the levels of 21 mineral elements (including the bulk elements: Ca, P, Mg, K, Na; trace elements: Li, Cr, Mn, Co, Cu, Zn, Se, Mo; and toxic elements: Be, Al, As, Cd, Sb, Ba, Pb, Ni) in the bone marrow, plasma, bones, and first antlers of farmed fallow deer (Dama dama). The mineral compositions of tissues were analyzed using inductively coupled plasma mass spectrometry. Higher concentrations of Ca, P, Mg, Cr, Zn, Se, Al, Ba and Ni were found in bone marrow than in plasma. The highest concentrations of Ca, P and Ba were recorded in fallow deer bone, while the highest concentrations of Mg, K, Na, Li, Cr, Mn, Co, Cu, Zn, Se, Mo, Be, Al, As, Sb, Pb and Ni were found in the antlers. Moreover, the research showed a significant negative relationship between Ca and Cd, and between Ca and Pb, and P and Pb (rS = −0.70, rS = −0.80, and rS = −0.66, respectively; p < 0.05) in the tissues.

Comparison of the accumulation of macro- and microelements in the bone marrow and bone of wild and farmed red deer (Cervus elaphus)

Background

The cells of the entire body, including the skeletal system, especially of young animals, may derive from the bone marrow in which they multiply. Therefore, it is important to assess whether the diet and quality of life of deer have a significant impact on the elemental composition of bone and bone marrow, which can directly affect their health and growth. The aim of this study was to determine the concentrations of macro- (Ca, calcium, P, phosphorus, Mg, magnesium, K, potassium, Na, sodium) and microelements (Li, lithium, Cr, chromium, Mn, manganese, Co, cobalt, Cu, copper, Zn, zinc, Se, selenium, Mo, molybdenum, and Sn, tin) accumulated in the bone marrow and bones of deer (Cervus elaphus). The study was carried out on 15 young stags divided into two groups: farmed and wild animals. The concentrations of macro- and microelements were analysed using the inductively coupled plasma mass spectrometry technique. This research expands our knowledge on this topic, which so far has not been extensively studied.

Results

The mean content of K, Na, Zn and Se in the bone marrow of farmed animals was significantly higher than in wild deer, whereas the mean content of Ca, P, Mg, K, Na and Li in the bones was higher in wild animals than in farmed individuals (p < 0.05). In addition, the mean concentration of Cr, Mn, Cu, Se and Mo in the bones of the analysed animals differed significantly (p < 0.05) and was higher in the farmed deer. The mean concentration of Se in the bone marrow of wild deer decreased with the increase of the body weight (p < 0.05). In turn, the mean content of Mn in the bone marrow and of Mo in the bones of the animals was significantly positively correlated with the animals’ body weight (p < 0.05).

Conclusions

The obtained results indicated different levels of micro- and macro-components in the body of farmed and wild deer, though without clear and strong variations. Generally, the higher level of macronutrients in the bones of wild deer may be related to the higher physiological importance of these minerals for life activities in the natural environment and to the limited supply of balanced food. On the other hand, the higher levels of microelements in the tissues of farmed animals may result from their significantly better nutritional status in the first year of life, achieved through appropriate nutrition as well as diet supplementation of adult females.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-03041-2.

Effects of supplementation with different levels of calcium and phosphorus on mineral content of first antler, bone, muscle, and liver of farmed fallow deer (Dama dama)

Nutrition is one of the main factors influencing physiological processes, e.g., growth and antler development, in Cervidae. The aim of this study was to demonstrate a possible effect of supplementation with different levels of calcium (Ca) and phosphorus (P) on the mineral composition of antlers and bones, and its effect on the content of macroelements — Ca, potassium (K), magnesium (Mg), sodium (Na), and P — in the muscle tissue, liver, and blood of farmed fallow deer fawns. The results show a positive effect of increased doses of Ca and P on body weight at the age of 14 mo. Additionally, there was a significant increase in the content of Ca, Mg, Na, and P in antlers and Ca, Na, and P in bones. The muscle tissue was characterised by a significant increase only in the content of Na, whereas Ca, K, and P levels increased significantly in the liver. In turn, the serum P content decreased significantly. Adequate Ca and P supplementation exerts a positive effect on the mineral composition of bones and whole antlers of farmed fallow deer fawns, and it enhances the concentrations of macroelements in tissues, which may constitute a reservoir used for future development of antlers. It also has a positive effect on body weight.

Antlers - Evolution, development, structure, composition, and biomechanics of an outstanding type of bone

Antlers are bony appendages of deer that undergo periodic regeneration from the top of permanent outgrowths (the pedicles) of the frontal bones. Of the "less familiar" bone types whose study was advocated by John Currey to gain a better understanding of structure-function relationships of mineralized tissues and organs, antlers were of special interest to him. The present review summarizes our current knowledge about the evolution, development, structure, mineralization, and biomechanics of antlers and how their formation is affected by environmental factors like nutrition. Furthermore, the potential role of antlers as a model in bone biology and several fields of biomedicine as well as their use as a monitoring tool in environmental studies are discussed.

Effect of Ca and P supplementation on the haematological parameters and content of selected minerals in the blood of young farmed fallow deer males (Dama dama)

The aim of the study was to assess the effect of supplementation of feed rations with increased calcium and phosphorus doses on the haematological parameters and plasma zinc (Zn), phosphorus (P), magnesium (Mg), copper (Cu), calcium (Ca), and iron (Fe) content as well as the body weight and the growth and development of the first antler in farmed fallow deer (Dama dama Linnaeus, 1758). The mean level of erythrocytes (RBC), haemoglobin (HGB), and haematocrit (HCT) was increased in the Ca- and P-supplemented group after the treatment period. The change was statistically significant (p < 0.05) in the case of RBC and HCT. The other haematological parameters (mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and platelet count (PLT)) were reduced. An increase in the Zn content was observed in the plasma of slaughtered animals. The concentration of other minerals (P, Mg, and Cu only in group II receiving a higher level of Ca and P in the feeding dose; Ca and Fe only in group I supplemented with a lower content of Ca and P in a nutritional dose) in blood plasma decreased slightly after the supplementation period and declined further after the slaughter. Noteworthy, there was a significant increase in the plasma Cu and Fe levels in group I in group II, respectively, in the post-supplementation period. No significant differences were observed in the body weight between the groups, but there was a beneficial effect of the higher Ca and P dose in the feed ration for the farmed fallow deer on the length of the first antler (p < 0.05). The antlers of animals in group II were on average 2.3 cm longer than in group I.

Effects of Mn supplementation in late-gestating and lactating red deer (Cervus elaphus hispanicus) on milk production, milk composition, and calf growth

This study describes the effects of Mn supplementation of 20 late-gestating and lactating Iberian red deer (Cervus elaphus hispanicus) females (hinds) fed a balanced diet on milk production and milk composition over the lactation period. Body weight of their calves at birth and at weaning was also evaluated. In addition, the effect of lactation stage was studied. For these purposes, 2 groups of hinds, one composed by 12 individuals (experimental) and the other by 8 individuals (control) were compared. Experimental hinds were s.c. injected weekly with Mn (2 mg Mn/kg BW) from day 140 of gestation until the end of lactation (week 18; forced weaning by physical separation). Control hinds were injected with a physiological saline solution with the same volume and at the same frequency as the experimental group. Serum Mn content of hinds was assessed just before the first Mn injection and at week 10 of lactation to assess whether the injected Mn increased Mn concentrations in blood. No differences were observed for BW of calves at birth but calves whose mothers were injected with Mn tended (P = 0.07) to have greater gain of BW from birth to weaning in proportion of BW at birth compared to calves from control hinds. In addition, supplementation with Mn increased (P ≤ 0.05) daily milk production by 10.2%, milk fat content by 11.2%, and total fat yield by 17.8%. Also, milk from hinds supplemented with Mn had more Ca (P < 0.001) and P (P < 0.05) than milk from control hinds. Manganese supplementation did not influence Mn serum content when blood was analyzed at week 10 of lactation, but increased the Mn content of milk by 18.3% (P < 0.001). Lactation stage affected (P < 0.001) fat, protein, lactose, and DM. Their contents increased as lactation proceeded, and protein was substituted by fat. Therefore, results suggest that Mn supplementation of hinds is recommended, even when they are fed a balanced diet, to increase milk production and the content of fat, Ca, P, and Mn of milk.

The bony horncore of the common eland (Taurotragus oryx): composition and mechanical properties of a spiral fighting structure

Horns are permanent structures projecting from the head of bovids, consisting of a bony horncore covered with a layer of skin and then a sheath of keratinous material showing variability of growth intensity based on nutrition. From the point of view of the horn's mechanical properties, the keratin sheath has been widely studied, but only a few studies have considered the complete structure of the horn and fewer studies have focused on the bony horncore and its characteristics. The latter showed the important role of the bony core, when cranial appendages are subject to mechanical stress (as happens during fighting). The mechanical properties of bone material, along with its mineral profile, are also important, because they can show effects of different factors, such as nutrition and mineral deficiencies in diet. For this reason, eight horncores of captive common eland male were sampled at four positions along the vertical axis of the horn. The main aim was to study variation in mechanical properties and the mineral content along the vertical axis of the horncores. We further analysed whether the spiral bony ridge present on eland horncores differs in any of the studied properties from adjacent parts of the horncore. In other antelopes, spiral ridges on the horns have been proposed to increase grip during wrestling between males. Cross-sections of the horncores were performed at four positions along the longitudinal axis and, for each position, two bone bars were extracted to be tested in impact and bending. Moreover, in the first sampling position (the closest position to the base) two bars were extracted from the spiralled bony area. The resulting fragments were used to measure ash content, bone density and mineral content. Results showed that horn bone decreased along the vertical axis, in ash (-36%), density (-32%), and in impact work 'U' (marginally significant but large effect: -48%). The concentration of several minerals decreased significantly (Mg, Cr, Mn and Tl by -33%, -25%, -31%, -43%, respectively) between the basal and the uppermost sampling site. The bone tissue of the horncore spiral compared with non-spiral bone of the same position showed a lower ash content (53% vs. 57%), Mg and Mn; in addition to showing approximately half values in work to peak force 'W', bending strength 'BS' and 'U', but not in Young's modulus of elasticity 'E'. In conclusion, similarly to the results in a totally different fighting bony structure, the antlers, the horncore of eland shows advantageous parameters in bone tissue of the base in respect to the tip, with higher values for mechanical properties, density and mineral profile. Moreover, the spiral bone tissue showed lower material mechanical properties. Probably the spiral tissue of the horn may have a role in deflecting potential cross-sectional fractures during wrestling. In addition, it may serve to improve the grip during wrestling, and we propose that it may also prevent risk of rotation of sheath with respect to internal bone not only in this, but also in other straight bovid horns.

Manganese Supplementation in Deer under Balanced Diet Increases Impact Energy and Contents in Minerals of Antler Bone Tissue

Bone ash, collagen, Ca and P composition, are considered the main factors affecting mechanical properties in bones. However, a series of studies in bone and antler have shown that some trace minerals, such as manganese, may play a role whose importance exceeds what may be expected considering their low content. A previous study showed that a reduction in manganese in antlers during a year of late winter frosts led to generalized antler breakage in Spain, which included a reduction of 30% of cortical thickness, 27% reduction in impact energy, and 10% reduction in work to peak force. Starting for this observation, we experimentally studied the effects of manganese supplementation in adults and yearling (yearlings) red deer under a balanced diet. Subjects were 29 deer of different age classes (adult n = 19, yearlings n = 10) that were divided in a manganese injected group (n = 14) and a control group (n = 15). Antler content in ashes and minerals, intrinsic mechanical properties and cross section structure were examined at 4 points along the antler beam. A one way ANOVA (mean per antler) showed that in yearlings, manganese supplementation only increased its content and that of Fe. However, in adults, Mn supplementation increased the mean content per antler of Ca, Na, P, B, Co, Cu, K, Mn, Ni, Se (while Si content was reduced), and impact work but not Young's modulus of elasticity, bending strength or work to peak force. A GLM series on characteristics in the uppermost part examined in the antler, often showing physiological exhaustion and depletion of body stores, showed also a 16% increase in work to peak force in the antlers of the treated group. Thus, manganese supplementation altered mineral composition of antler and improved structure and some mechanical properties despite animals having a balanced diet.

Element concentrations and element ratios in antler and pedicle bone of yearling red deer (Cervus elaphus) stags-a quantitative X-ray fluorescence study

The present study compared the concentrations of different elements (Ca, P, Mg, Sr, Ba, K, S, Zn, Mn) as well as Ca/P, Ca/Mg, Sr/Ca, and Ba/Ca ratios in hard antler and pedicle bone of yearling red deer stags (n = 11). Pedicles showed higher concentrations of calcium and phosphorus and a higher Ca/Mg ratio than antlers, while antlers exhibited higher concentrations of potassium, sulfur, and manganese as well as higher Ca/P, Sr/Ca, and Ba/Ca ratios. The findings indicate that antlers are less mineralized and show less maturation of their bone mineral than pedicles. Antlers also showed a higher intrasample variation of mineralization than pedicles, which can be related to the shorter life span of the (deciduous) antlers compared to the (permanent) pedicles. It is suggested that antler bone formation is stopped before the theoretically possible degree of mineralization and mineral maturation is reached, resulting in antler biomechanical properties (high bending strength and work to fracture) that are well suited for their role in intraspecific fighting. It is further suggested that the differences in Sr/Ca and Ba/Ca ratios of antlers and pedicles are related to the dietary shift from milk to vegetation in combination with an increasing intestinal discrimination against Sr and Ba with age, resulting in a less marked difference in these ratios than would be expected based on the dietary shift alone. The findings of our study underscore the suitability of antlers and pedicles as models of bone mineralization and the influence of different animal-related and/or external factors on this process.