The aim of this study was to determine the possibility of using duckweed in sustainable livestock production and aquaculture. Duckweed is a small plant which grows in water and is exploited in biotechnology, dietetics, phytotherapy, and ecotoxicology. It is also used for biological waste-water treatment, and for biogas and ethanol production. This study provides the characteristics of duckweed and presents results indicating its applicability in livestock feeding. Duckweed is a rich source of proteins and amino acids, and contains many macro- and micronutrients as well as vitamins and carotenoids. Unfortunately, it accumulates considerable amounts of toxic metals and compounds from the aquatic environment, which may limit its use as a feed ingredient. Fresh or dried duckweed is willingly consumed by animals (poultry – laying hens, broiler chickens, ducks; cows, sheep, goats, swine, fish) and is a valuable protein source to them. It has been scientifically demonstrated that its use in moderate amounts or as a partial replacement of other protein feed materials, including soybean meal, has a beneficial effect on the productivity, fattening, and slaughter performance of livestock and poultry as well as on the quality of their meat and eggs. Research addressing duckweed use as a feed ingredient should focus on developing various growth media technologies, including the use of slurry digestate, to obtain high biomass yields. Another research direction should be to determine risks in the production chain (collection, processing), which limit its use in monogastric and ruminant diets.

This study aimed to explain the possibility of partial replacement of genetically-modified soybean meal (SBM GM) with pea seeds and rapeseed meal (RSM) in complete feed mixtures for growing-finishing pigs and to determine its impact on meat quality and health-promoting indices. The pigs (n = 50) were randomly divided into five groups, 10 animals each (gilts and barrows, 1:1, 3-breed: ♀ (landrace × yorkshire) × ♂ duroc), including the control group (C) and four experimental groups (E1, E2, E3, E4), and fed complete feed mixtures. The SBM GM was the only protein source in feed mixtures for control pigs. In feed mixtures for E1–E4 groups, it was partially replaced with pea seed doses of 5.0%, 10.0%, 15.0%, and 17.5% in groups E1, E2, E3, and E4, respectively. The feed mixtures were iso-energetic and iso-protein. After completed fattening, the animals were slaughtered. M. longissimus lumborum was sampled for analyses of the chemical and physical traits. The fatty acid profile determined in intramuscular fat (IMF) was used to compute the values of the health-promoting indices. The chemical and physical characteristics of meat were comparable in all groups. The study showed a dietetically-beneficial decrease in the values of atherogenicity index (AI), thrombogenicity index (TI), and saturation (S/P) in the meat of the experimental pigs vs. control group. The values of most of the analyzed quality attributes of pork justify using alternative protein sources as partial SBM GM replacers in diets for growing-finishing pigs in sustainable animal production.

The aim of the study was to examine the assimilability of organic and inorganic selenium supplied as an additive to pig feed. The influence of both selenium forms on pig slaughter value as well as on the physicochemical and sensory characteristics of meat was also examined (experiment I). An attempt to establish the distribution of selenium in the body of experimental fatteners was made (experiment II). Experiment I was performed on 20 carcasses of crossbred pigs of (Polish Large White × Polish Landrace) × Duroc genotype and experiment II was carried out on 45 samples of longissimus and semimembranosus muscles taken from fatteners of the same genotype (PLW × PL × Duroc). The results obtained indicated that selenium supplementation in the diet had no impact on slaughter performance, meat quality and most physicochemical and sensory characteristics of meat. Selenium was found to have no significant effect on meat colour. The meat water holding capacity (WHC) was lower in the group of pigs fed organic selenium. The highest selenium concentration was found in the semimembranosus muscle of fatteners receiving the inorganic selenium additive.

Duckweed is a plant with high phytoremediation abilities, which is why it is used in the process of cleaning the aquatic environment. The present study aimed to determine the effect of various concentrations of pig slurry added to the growth media used to produce duckweed (Lemna minor) (laboratory Warsaw University of Life Sciences—SGGW) (experimental groups 1–9, pig slurry concentration (%): 1—2.00, 2—1.50, 3—1.00, 4—0.75, 5—0.50, 6—0.25, 7—0.12, 8—0.06, 9—0.03, control group 0—0.00). The contents of nutrients in the growth media could be classified as high (gr. 1–3), optimal (gr. 4–6), and deficient (gr. 7–9). Analyses were conducted for duckweed yield and growth medium parameters (pig slurry concentration, pH, salinity, temperature, TDS, and EC) on days 0, 10, 20, and 30 of the experiment. No growth or poor growth of duckweed were noted in groups 1, 6–9, and 0. In turn, satisfactory yields of duckweed green mass were recorded in groups 3–5, which allowed choosing them for further observations and analyses, including proximate composition (including protein content); contents of Ca, Mg, K, Na, Zn, Cu, Cd, Pb, Al, Cr, and α-tocopherol; and carotenoids—β-carotene, α-carotene, violaxanthin, zeaxanthin, lutein, amino acids, fatty acids as well as N-NH₄ and N-NO₃. The plant material had an acceptable proximate composition and nutritionally safe analyzed component contents. Appropriate, stable growth medium conditions allowed the production of satisfactory duckweed yields. The study results allowed us to conclude that it is feasible to obtain feed material meeting basic quality standards by maintaining a closed circuit of duckweed culture, and use in the agricultural environment is possible through harnessing pig slurry for its production and ensuring its optimal growth conditions.