Seasonal Variation in Chemical Composition, Ruminal Fermentation, and Biological Characteristics of Paulownia shan tong: In Vitro Potential Use by Sheep and Goats

This study was conducted to determine the seasonal variation (two seasonal harvests during winter and spring) in some chemical and biochemical characteristics of Paulownia shan tong leaves. To achieve this, we analyzed the chemical composition in terms of dry matter (DM), organic matter (OM), crude protein (CP), cell-wall content (neutral detergent fiber (NDF)), acid detergent fiber (ADF), acid detergent lignin (ADL), and lipids. The phenolic compounds (PC) and antioxidant activity (AA) of the leaves were also determined. In vitro gas production (GP) and nutrient degradability were evaluated using two ruminal-content donors (sheep and goats). Higher (p < 0.05) antioxidant activities were observed in the winter harvest of P. shan tong, while higher concentrations of OM (90.5%), lipids (3.02%), NDF (69.7%), ADF (54.8%), ADL (35.4%), total flavonoids (0.45 mg catechin equivalents/mg DM), and total phenolics (2.52 mg gallic acid equivalents/mg DM) were observed in the spring harvest. Higher asymptotic GP and rate of GP (p < 0.05) were observed when the leaves were incubated with rumen liquor of goats compared to sheep; however, higher (p < 0.05) lag time of GP and half-time of GP were observed with rumen liquor from sheep. Moreover, higher asymptotic GP, rate of GP, and half-time of GP were observed with the winter harvest of P. shan tong. Higher (p < 0.001) metabolizable energy, OM degradability, and microbial protein supplies were obtained when the leaves were incubated with rumen fluids from goats and from the winter harvest of P. shan tong compared to the spring harvest. In conclusion, based on the chemical composition and the kinetics of in vitro gas production, P. shan tong leaves seem to be characterized by a good nutritive value and could be considered as an alternative feed resource for ruminants.

Phytophthora Root and Collar Rot of Paulownia, a New Disease for Europe

Paulownia species are fast growing trees native to China, which are being grown in managed plantings in several European countries for the production of wood and biomasses. In 2018, wilting, stunting, leaf yellowing, and collapse, as a consequence of root and crown rot, were observed in around 40% of trees of a 2-year-old planting of Paulownia elongata × P. fortunei in Calabria (Southern Italy). Two species of Phytophthora were consistently recovered from roots, basal stem bark, and rhizosphere soil of symptomatic trees and were identified as Ph. nicotianae and Ph. palmivora on the basis of both morphological characteristics and phylogenetic analysis of rDNA ITS sequences. Koch’s postulates were fulfilled by reproducing the symptoms on potted paulownia saplings transplanted into infested soil or stem-inoculated by wounding. Both Phytophthora species were pathogenic and caused root rot and stem cankers. Even though P. palmivora was the only species recovered from roots of naturally infected plants, in pathogenicity tests through infested soil P. nicotianae was more virulent. This is the first report of Phytophthora root and crown rot of a Paulownia species in Europe. Strategies to prevent this emerging disease include the use of healthy nursery plants, choice of well-drained soils for new plantations, and proper irrigation management.

Optimization of Micropropagation and Genetic Transformation Protocols for Paulownia elongata : A Short Rotation Fast Growing Bioenergy Tree

Various steps of micropropagation include selection of suitable explant, establishment of adventitious shoot induction cultures, proliferation, rooting, and acclimatization of the resulting plantlets. A systematic protocol is provided for the micropropagation and Agrobacterium tumefaciens-mediated genetic transformation of a fast growing, multipurpose tree, Paulownia elongata. Our studies show that optimum shoot induction is on half leaf with petiole explant on MS medium supplemented with 25 μM thidiazuron and 10 μM indole-3 acetic acid. Micropropagation protocols provided here are applicable to explants collected from the primed in vitro raised seedlings on MS medium containing 2.5 μM 6-benzylaminopurine (BAP) or actively growing shoots collected from greenhouse or field growing plants. We also discuss a possible role of "Python" script guided protocol optimization for higher and consistent multiplication of shoots that can be very helpful for scaled up production in commercial settings. To facilitate future plant improvement and gene editing possibilities, an A. tumefaciens based genetic transformation protocol and molecular identification of transgenic plants using Polymerase Chain Reaction (PCR) and Reverse Transcriptase-PCR (RT-PCR) techniques have also been optimized.

Phytochemical characteristics of Paulownia trees wastes and its use as unconventional feedstuff in animal feed

Due to the continuous increase in animal feed prices, and the presence of competition between humans and animals on food materials, it is imperative to identify other non-food plant resources to assist the animal feed industry and improve livestock productivity. Plant wastes may cause air, soil, and water pollution. However, if judiciously managed, they would be important resources. Plant wastes are used as feedstuffs and fertilizers. However, their use as animal feed is more useful than fertilizers. Because of the high content of fiber and non-protein N, these wastes are more valuable for feeding ruminants than poultry. The use of the plant wastes as feedstuffs could improve the environmental quality and profits for feed producers. Paulownias are fast-growing trees initially cultivated for wood production. However, due to their good nutritive value, their leaves have been used for ruminants, non-ruminants animals and poultry feeding. Furthermore, they are well-known for its medicinal and antibacterial properties. However, little is still known about its characteristics. This review aimed at providing detailed information about the nature, nutritional value, phytochemicals, and uses of Paulownia as a promising feedstuff in the fields of ruminants, non-ruminants, and poultry nutrition.

Paulownia Leaves as A New Feed Resource: Chemical Composition and Effects on Growth, Carcasses, Digestibility, Blood Biochemistry, and Intestinal Bacterial Populations of Growing Rabbits

Simple Summary

Paulownia trees are grown as a woody biofuel crop, and they yield large amounts of leafy biomass rich in nitrogen. However, there is limited information on the use of paulownia leaves as an animal feed resource. Hence, this study was conducted to assess the effects of paulownia leaf meal (0%, 15%, and 30% in diets) on the growth performance, nutrient digestibility, blood biochemistry, and intestinal microbiota of growing rabbits. The chemical analyses of paulownia leaves indicated that most of the nutrients are similar to those in alfalfa hay. The in vivo results showed that the use of up to 15% paulownia leaf meal instead of alfalfa hay in the diets of the rabbits did not have any negative effects on their performance, nutrient digestibility, and blood constituents. In addition, a notable reduction in both cecal and feed pathogenic bacteria was observed when paulownia leaf meal was included in the diets.

Abstract

This experiment was conducted to study the effects of paulownia leaf meal (PLM) as a nontraditional feed on the growth, carcasses, digestibility, blood chemistry, and intestinal microbiota of growing rabbits. Sixty rabbits (5-weeks old) were randomly allotted to three dietary treatments containing three amounts of PLM (0%, 15%, and 30%). The results showed that PLM has a higher content of ether extract, organic matter, methionine, tyrosine, histidine, manganese, and zinc than alfalfa hay. Body weight gain decreased when 30% PLM was provided. The best feed conversion ratio was recorded in the rabbits fed 15% PLM. A notable increase in high-density lipoprotein levels with a significant decrease in low-density lipoprotein was noted in the rabbits fed the PLM diets. Total fungi and Enterobacteriaceae and total bacterial count in the feed were significantly reduced because of PLM. In the cecum, coliforms, Enterobacteriaceae species, and total bacterial count declined in the rabbits fed the PLM diets. Conclusively, up to 15% PLM can be used in rabbit diets without any deleterious effects on the performance, nutrient digestibility, and blood constituents. In addition, dietary inclusion of PLM has the potential to reduce cecal pathogenic bacteria in rabbits.