Optimal diet strategy of a large-bodied psittacine: food resource abundance and nutritional content enable facultative dietary specialization by the Military Macaw

Background:Dietary specialization should arise when there is a relatively high abundance of a particular resource,where animals may select food items to obtain an optimal diet that maximizes energy intake.Large‑bodied psittacines frequently exhibit a narrow dietary niche with specific habitat use,but few studies have determined whether psittacines select food resources,and how this influences habitat use.Methods:We established fruiting phenology transects to evaluate food resource availability for the large‑bodied Military Macaw(Ara militaris)in semi‑deciduous,deciduous,and pine‑oak forest at two sites along the coast of Jalisco,during the dry season when macaws are nesting.We also determined Military Macaw diet by observations of foraging macaws along transect routes,and conducted bromatological analysis of the nutritional content of the most consumed resource.Results:Military Macaws used six plant species as food items during the dry season,and had a narrow dietary niche(Levins’B=0.28),with 56%of foraging macaws consuming the seeds of Hura polyandra.No food resources were recorded in pine‑oak forest during the dry season,with food resources and foraging by macaws concentrated in tropical deciduous and semi‑deciduous forest,where H.polyandra was the most abundant fruiting tree species.When considering the proportional availability of food resources,we determined a broad Hurlbert dietary niche breadth of H=0.67,indicating that Military Macaws consumed food resources according to their availability.Furthermore,the seeds of H.polyandra were an important source of protein,carbohydrates,minerals and moisture,and the hard fruitcasing means that these seeds are exclusively available for macaws.Conclusions:By concentrating their diet on the most abundant resources,Military Macaws may increase foraging efficiency in the dry season.The high nutrient content also means that concentrating the diet on seeds of H.polyandra may be an optimal foraging strategy for Military Macaws to meet their energy requirements during the breeding season.

Yield and Characterization of the Centesimal Composition of Amazonian Estuarine Fish

Fish, as one of the fishery resources, is an important constituent of the diet of the Amazon population, as it is the source of several nutritional components. The present work aimed to characterize the centesimal composition of Plagioscion squamosissimus fillet (n = 10) and Macrobrachium amazonicum meat (n = 82), species acquired in the estuarine region of the state of Amapá, Brazil. Carcass yield, as well as protein, water content, lipids and ashes was determined according to the methodologies proposed by the Adolf Lutz Institute, as well as carbohydrate and caloric determinations. The analyses were performed in triplicate per sample. After comparing with the literature, it was possible to conclude that P. squamosissimus presented a fillet yield of 31.11%± 0.61%, high protein content (15.99 ± 1.26 g/100 g) and humidity (79.40 ± 1.10 g/100 g), moderate contents of mineral residues (1.10 ± 0.07 g/100 g) and carbohydrates (0.96 ± 0.90 g/100 g), low lipid contents (2.29 ± 0.65 g/100 g), as well as low caloric values (385,018.12 J/100 g) and M. amazonicum a meat yield of 44.12%± 8.34%, high levels of protein (22.81 ± 1.72 g/100 g), carbohydrates (1.92 ± 1.61 g/100 g) and mineral residues (1.76 ± 0.78 g/100 g), moderate water content (73.38 ± 0.78 g/100 g), low lipid levels (0.43 ± 0.08 g/100 g), as well as low caloric values (440,786.3 J/100 g). The results obtained in this work can serve as a subsidy in nutritional diets for humans, thus allowing an adequate dietary use of these species.

Fertilization of Tifton 85 with Swine Liquid Manure

The objective was to verify the possibility of supplying the nutritional requirement of Tifton 85 grass with swine liquid manure in an intensive management system. The experiment was carried out in a randomized block design, with four treatments of swine liquid manure doses: 0, 70, 140 and 210 m3·ha-1, divided into seven applications and a treatment of mineral fertilization of 200 kg of nitrogen ha-1·year-1. Samples of the collected plant material were weighed to obtain fresh mass taken for drying and then ground for bromatological determination. The dry mass production data were obtained by dry matter accumulation during the cuts and averages were made for the variables;plant height, crude protein, NDF, ADF, neutral detergent insoluble protein (NDIP) and acid detergent insoluble protein (ADIP). The data were subjected to variance analysis, performing regression for swine liquid manure doses and averages test (Dunnett test) to compare the doses with the mineral fertilization. Higher plant heights, dry mass production, crude protein content, neutral detergent insoluble protein content and lower neutral detergent fiber content in Tifton 85 grass were observed with mineral fertilization. In the variables, acid detergent fiber and acid detergent insoluble protein there was no difference (P = 0.05) between the mineral fertilization and the swine liquid manure doses. There was a linear increase (P = 0.05) of swine liquid manure doses only in dry matter production. Swine liquid manure doses up to 210 m3·ha-1·year-1 do not meet the entire nutritional requirement of Tifton 85 grass, recommending the evaluation of higher swine liquid manure doses or complementation with mineral fertilization.